Is there a key success factor on grass, and if so, what is it? I say everyone's serve is better on grass, so that's not the key success factor - that's a myth.
It's the return.
Recently Rafael Nadal opined that "If your serve is good, you can win on grass even without playing your best." The missing context is that he was clearly explaining how he had won his first tournament on grass without much preparation and without much of a good run of form to speak of leading into the tournament. But not surprisingly it kicked off an extended debate in the blogosphere about the validity of results on grass, because of the influence of the serve.
I think what Nadal implied (without really meaning to) is that you can lose a match - any match - on grass to a player who serves exceptionally well on the day, and he's right. That's one of the reasons why Wimbledon is so hard to win: because you can so easily lose any single match if you have a bad day and your opponent (no matter who he is) serves his socks off. But unlike what was immediately interpreted as a dig at grass court tennis (something that Nadal, who has always professed his love of Wimbledon and grass court tennis, would never do), you really can't win Wimbledon with just a big serve.
That is just a myth.
The universe of players who have won Wimbledon is much smaller than other majors, and it does not necessarily reflect players with the biggest serve. Serving well (and not necessarily big) like Federer and Sampras helps a great deal, but you have to serve well, not just big. In fact, I think the reason why Federer and Sampras have won so many Wimbledons, and why the universe of champions at Wimbledon is smaller than the other majors, is precisely because the serve is not the deciding factor in whether you can win it. Take the following statistics:
# of different FO champions in the open era = 26
# of different Wimbledon champions in the open era = 20
# of different FO champions in the last 20 years = 12
# of different Wimbledon champions in the last 20 years = 8
I don't mean to denigrate Roland Garros, but just as the universe of players who have won 250's is greater than those who have won 500's which is greater than those who have won 1000's which is greater than those who have won majors, the derived conclusion is that the harder it is to win the tournament, the smaller the universe of players who actually do it. So, by this logic, that the universe of players who have won the FO is greater than the universe of players who have won Wimbledon would suggest that Wimbledon is harder to win. If you doubt this conclusion, you must accept the opposite: that the 250's are the hardest to win, and that just doesn't fly.
The reason the 500s are harder than 250s is that the field is typically stronger, because there are more points at stake, and they are more coveted. That is precisely the point of the comparison, and transitively the comparison carries through to each level of more and more coveted titles, including comparing the majors. Again, no denigration of the the tournaments that lose out in the comparison, but merely a logical conclusion from the evidence of the universe of players who've won the title.
Now, because Federer and Sampras have such great serves, the assumption is that the better your serve, the more likely you are to win Wimbledon. As such, when sizing up a player's chances, or predicting the result of a particular match, the serves are frequently compared to determine who has the advantage. But I am of the opinion that comparing serves is actually off the mark. You are mixing and matching two things - one doesn't compare serves - that is irrelevant because only one player at a time serves. One compares the serve of one to the return of the other. A player with a big serve can escape losses to other players with big serves if they return well. It is rare that players with really big serves return well, and also why players with just big serves (and little else to their game) rarely win Wimbledon.
Goran Ivanisevic is a perfect example - that man had the biggest and best serve in the history of tennis, but he won Wimbledon exactly once almost by accident. In his best chance (on paper anyway), in 1992 he lost to Andre Agassi, a player with a relatively weak serve but a relatively oustanding return (who happened to beat Boris Becker and John McEnroe along the way - not exactly slouches in the serve department). Ivanisevic's other Wimbledon final losses were to another player with a great serve - Pete Sampras. So what distinguished the two?
The return - Sampras' was a better (as well as the rest of his game - but I digress).
So a big serve gets you a chance to win a match or two here or there - but if you want to win Wimbledon, you need more than a big serve. You need the whole package including a good serve. But only the best of the best have the whole package, and as such, relatively few players have won Wimbledon as compared to say, the French Open, where a lot of players that did not have the full package, have won relatively more titles than have done so at a Wimbledon.
The logic and the stats on the universe of players who have won Wimbledon versus Roland Garros is very underrated, but it is not a matter of opinion. As for the effect of the serve on grass, it is inversely overrated - Nadal has 2 Wimbledons, Djokovic 2, Murray 1, even Federer at 7 titles...not one of them could be said to have one of the biggest serves on tour, earning a lot of "cheap" points. Roddick had a huge serve, but consistently lost to players who returned better than him (after all, so few serve better than him they must have had better returns). Ivanisevic had the biggest serve ever and he won once, each time he lost to a player, not with a better serve, but a better return.
To win at Wimbledon you need a good serve among many things, but it is not the deciding factor - the return is. Of course, even a good return (alone) isn't enough - you need the full package. You have to be able to attack and defend, you need decent volleys, but most importantly you need a good serve, because everybody gets a little help on the serve on grass. That the serve is the deciding factor to winning Wimbledon is a myth of grass court tennis that has persisted for years since the late 40's when serve and volley tennis became a full time tactical approach. There have been a lot of players with great serves who have not won Wimbledon, but almost none with bad returns, and certainly no multiple champions with a poor return of serve.
An example of this is Ivan Lendl - his biggest problem on grass wasn't his serve (which was excellent) it was his return, which he was never able to master on grass, despite years of trying. Lendl just wasn't that talented, and as a result he needed time and a certain bounce to return well, which he would get on clay or hard courts, and won many majors on those surfaces - what foiled him on grass was the return. Lendl's talent limited his return against the best players with the best serves - this is not an on/off proposition as in "either you're talented enough or not" - it does depend on the guy across the net. He had as good a serve as the players he lost to, with perhaps the exception of Becker, but he lost to a lot more players than Becker, his problem against those players he lost to was that he couldn't make any headway in his returns. His own serve was excellent. Just because your return isn't good enough against Edberg, Becker and Pat Cash, doesn't mean it won't be good enough against Jeff Tarango or Brad Gilbert.
Go down the list of players with the biggest serves on tour over the last 40 years and remove those players with good returns (Colin Dibley, Ivan Ljubicic, Steven Denton, Mark Phillipousis, Kevin Curren, Bobo Zivojinovic, Greg Rusedski, Ivo Karlovic, Roscoe Tanner, Andy Roddick) and you'll have a very long list of players with big serves who have never won Wimbledon. Now, do the reverse - list the players with the best returns in the game, remove those with great serves and you'll still have a list of players who have won Wimbledon (Agassi, Borg, Connors, Nadal, Murray, Djokovic, etc.). That's just good analysis that dispels the myth that the deciding factor in winning Wimbledon is the serve. Remember that on grass everybody's serve is a little more effective because of the surface, therefore getting an edge over the field would necessarily come from being able to neutralize that phenomenon, not from benefitting from it, which everyone does and which does not give you an edge.
Whether the return is harder to master or acquire is not relevant - it is whether having an outstanding return or an outstanding serve is the deciding factor in whether you will win Wimbledon. Nadal, Murray, Djokovic, even Federer to some extent, rarely lead the ATP in aces, 1st percentage won or even service games won - and if they do, it isn't because they get a lot of free points on the serves like the Karlovic's, Isners, Lopez's, Tsonga's, Almagro's and Raonics of the world. They may use their serve better than this lot, but that's because they're better tennis players that are able to do more with less (on the serve). What they all do better than that lot is return of serve, and they've all won Wimbledon in the last 10 years - 3 of them more than once.
Counter-intuitive, I know, but true.
In fact, I'll go you one better - I don't even think it's even critical to have a great serve, to win Wimbledon, because there a lot of players who had just good serves and still won - therefore the serve cannot be the deciding factor in whether you will win Wimbledon. What Nadal referred to with the big serves is really a reference to the risk a great player runs of being dumped out of the tournament by a guy serving his socks off for one day, but without much of an overall game. That kind of player can be a spoiler, and there are a lot of spoilers at Wimbledon, and from that I conclude (along with the universe of players argument) that that's one big reason why Wimbledon is harder to win than the other majors. Particularly on grass, where everyone's serve is helped by the surface, there is a greater risk that a spoiler that can serve you off the court in one match.
That doesn't happen as often on other surfaces because the serve doesn't have as big effect - and that is the reason why at Wimbledon a great return is more important than a great serve. Because if you can't efficiently take advantage of the few opportunities you get to break serve (attack second serves, attack poorly placed first serves, or just get your racquet on the ball a lot), you will eventually run into someone who serves you off the court. The truly great players (among other things) have great returns, so they survive the serving mine field that is grass court tennis better than the other (numerous) players with great serves, but a minimal/weak return game - hence the cream really rises to the top at Wimbledon.
Sampras rarely served above 125mph, even at his best - there were always players on tour with bigger serves, but none with better serves - he used his to great effect. And it helps to use a great serve to great effect if you have the game to back it up, which Rusedski, Roddick, Ljubicic, Phillipousis, Ivanisevic and oh so many other big serving contemporaries did not have - and a big part of that overall game to back up whatever serve you may possess (good to great) is the return of serve. Federer also rarely serves big (130+), but his placement is outstanding, and nobody uses the serve to set up their game better than Federer - of course it helps that his game is outstanding, but the point is that it's not all down to the serve.
Riddle me this - why is it that Federer was so frequently able to out ace Roddick at Wimbledon when they played? Because his return was better, not because his serve was. And if I'm not mistaken, McEnroe never hit a serve over 120mph in his career, not so of the Roscoe Tanners and Kevin Curren's of his era - their serves were huge even by modern standards. But his overall game (including the return) was superior to both of those players, and as such he had more success at Wimbledon.
In fact, two of the biggest modern servers gave us an example in 2010 that put this distinction in relief: that absurd farce of a match between John Isner and Nicolas Mahut where the 5th set had 138 games in it, where it took Isner 69 games to break Mahut's serves.
Does anyone think that any of the players who've won Wimbledon in the last 10 years would take 69 games to break anyone's serve, let alone Nicolas Mahut's? Neither Isner nor Mahut have much of a return game to speak of, and not coincidentally neither has ever done anything significant at Wimbledon other than that match. They may win matches and/or smaller tournaments with depleted fields, but when the best of the best are all there, they just can't serve their way to glory - eventually their inability to return well catches up to them. That's not the case with the best players in the world. That's why only the best players in history win Wimbledon. And that's why Wimbledon is the hardest tournament to win.
And what of poor old Andy Roddick - the argument is that had it not been for Federer, he would have won 4 Wimbledons, right? I'm not so sure about that - after all, he lost to a lot more players at Wimbledon than just Roger Federer, and that Federer is a better player is a general statement which provides no insight - the better player doesn't always win (if that were the case, the trophy could be handed out at the draw). On grass, Federer bested Roddick as frequently as he did because he neutralized his serve with a great return of serve, which Roddick could never do. That was the deciding factor between them, not either of their serves which were both outstanding.
That's not to say that Federer's serve isn't really good - just not the equal of Roddick's - better game, obviously (especially the return) - but not the serve. But let's set that debatable example aside...can the serve possibly explain his losses to Murray (2006), Gasquet (2007), Randy Lu (2010), Tipsarevic (2008), Lopez (2011), Ferrer (2012)? Maybe Ivanisevic (2001), but that entire tournament was the outlier - he also lost to Rusedski in 2002, but in both matches to equally dominant serving players, the telling factor was the return - Rusedski broke Roddick 3 times 2002 and Ivanisevic twice in 2001...but he never broke either of them. And equally telling of Rusedski - he lost in the very next round....to Xavier Malisse. Now I can tell you that there were about 25 things Malisse did better than Rusedski, but the serve wasn't one of them - and if there were every a place where Rusedski should have put his serve to use against Malisse (if it were key) it would have been at Wimbledon. But surprise, surprise, Malisse broke Rusedski 3 times to 2.
To be honest, I watched Roddick play tennis for 10 years, and I can't ever remember him serving poorly - he may have, but it would have been exceedingly rare. It was the one part of his game that never broke down. But I have seen a lot of guys get a beat on his serve in one game and the rest of his game fell apart. He himself rarely broke serve on grass, precisely because it is so hard to do.
I should also point out something that is a logical extension of the "it's the return, stupid" argument: the better players have better returns of serve precisely because it requires more talent to consistently respond well to the easiest shot in the game to produce - i.e. the serve. For a good return you need particularly good hand-eye coordination, anticipation, consistent strike zone, balance, quickness, footwork, etc.). So a relative donkey, like Lukas Rosol can beat a great player from his serve, here and there, but win the tournament, no chance - not without a great return. There are a lot more players out there with great serves than players with great returns of serve - and it's no coincidence that they tend to do most of the winning. That's because it's harder to do than serve well, and as such it is a more telling factor in who wins the tournament - particularly on grass where the serve is helped so much by the surface, and everyone looks like a world beater with their serve - by the same token, only the best of the best appear to have even decent returns on grass.
My point here is that I'm trying to dispel the myth that the serve is the key/critical/deciding success factor on grass - it's not at all, it's the return. Some would limit their agreement if (and only if ) the serves are equal, but the serves are rarely equal and frequently the player with the better serve loses to the player with the better return. Therefore, it's pretty clear that the return is the key success factor and not the serve - of course your return has to be pretty good to beat a player with a great serve, especially on grass...but that's more to my point of why so few players have what it takes to win Wimbledon.
We've all fallen prey to the blurring of the lines defining the quality of the serve - if there is such a thing as a good serve, there must logically be great serves and below average serves - let's not lump everyone into sufficient/good/great serving category, cite Wimbledon champions (none of whom have a poor serve) and then claim that the key factor is something that they share in common with 90% of professional tennis players.
A key success factor is something that distinguishes players who've had success from those who have not. To point to the serve, which a large portion of players who have not won Wimbledon, and likely will never win, isn't informative. The return, however, is very probative. I happen to think that while the serve is the easiest stroke in tennis, because it's ball in hand, the return might be the hardest (because you must use a broad range of skills to respond to the easiest stroke in the game to hit at you), and by this logic, I am of the belief that the return, particularly at Wimbledon, where even the worst serves in tennis get a lot of help, is the most important stroke to winning the tournament.