It is the match the entire tennis world has been waiting for: the Nadal-Djokovic 2011 Roland Garros final. Although this still appears as a likely proposition, the two players could not have arrived in any more contrasting fashions.
First, let's take a look at Rafael Nadal. Nadal has been a shadow of himself ever since his awe-inspiring display in 2010, when he captured 3 slams, and in fact was looking for the Rafa slam at this year's Australian Open. Even his fourth-round win against Ljubicic was rather unconvincing. He was broken twice when he was well in command.
With Rafa Nadal, you always knew he needed just the slightest opportunity and he would capitalize. If he had his foot on the opponent's throat, he would go for the kill. This hasn't been the case lately. He has been getting away with it partially because of his doggedness, but also because of the quality of his opponents so far. However, he could find that the going will get tough against Novak Djokovic, and even Roger Federer for that matter.
For me the biggest difference has been his serve. I remember last year during Wimbledon and even more so during the US Open that his serve, which was never that much of a weapon during his initial years of success at Roland Garros, was lethal. I believe that his serve was the single most important reason he was able to dominate Novak in that US Open Final. Novak probably didn't have the same self-belief in that match that he has now, but still I think that had Rafa served then like he does now, Novak could have beaten him in the final. I'm not sure whether Rafa is playing through an injury, or if it's something bigger.
Fognini's withdrawal from the quarter-final match against Novak, although not significant from the point of view of Novak's semi-final or potential final, is still in my view, an irritant. I think Novak would have liked to take care of business against Fognini on the court and added to his streak. When a player is in the zone, as Novak is, they don't want interruptions; they just want to dominate their opponents. There is no doubt that he would have taken out Fognini, or Montanes for that matter, in three sets. The additional rest he has gained from not playing the quarter-final is, in my view, a non-factor in his potential semi-final against Roger.
Returning to the potential Rafa-Novak final, I think this match is critical for both players. Rafa wants to stop his losing streak against Novak. Importantly, he also doesn't want questions raised about his "Clay court King" status. He may lose on Clay eventually, but a loss to Novak—considering his recent performance—is not what Rafa wants. Make no mistake about it: Rafa does not want to lose to Novak in the French Final.
On the other hand this Final is extremely important for Novak as well. For all that he has achieved with the streak and the Australian, he wants this. He wants to beat Rafa at Roland Garros; to tame the lion in his own den. Should Novak defeat Rafa in the Final, I think this would easily be the most important win of his career. Should he loses, Rafa would have the psychological edge going forward, never mind the four consecutive wins Novak had against Rafa. This match is in some ways for Novak what the 2007 and 2008 Wimbledon finals were for Rafa against Roger. This win could propel Novak to greater heights.
Roger, himself, has been serving extremely well, and has looked good. As impossible as it seems, if he could in some way hold Djokovic he might fancy his chances against Rafa in the final, with the form Rafa has displayed recently. Roger definitely wants some payback against Novak for his recent losses, and against Rafa of course, his all-time nemesis.