Rafael Nadal is the king of clay. However, he has himself admitted that the advantages of clay are somewhat muted at Madrid due to the altitude which allows the balls to fly. So, his advantage is somewhat diminished here.
And while I'm certainly not one to insinuate that Rafa back down from a challenge, I clearly believe that there was a reason that he had to be pressured into playing this tournament and badmouthed it prior to it starting. This is the tournament that has the factors most likely to result in a loss right before the French Open. It's a case of there's not much to gain and a lot to lose by playing in Madrid, so why take unnecessary risks?
But, in the end, the pressures exerted on him to play in an event in his home country (and one which they are trying to tout as an up and coming potential 5th "Slam") were too much and he relented.
While a loss here will make no significant difference in the rankings or the seedings of upcoming tournaments, the last thing he needs is to lose his edge on the rest of the field. Consider this scenario...
By tomorrow's final, Rafa will be playing his fourth game in four days. He has just played a gruelling 4 hour match today against Djokovic. And he's been playing more tennis this clay court season than last. He won't be his freshest. Due to the mitigating conditions which seem to make this particular clay venue play more like a hard court (and Roger Federer is one of the best on hard surfaces), combined with the fact that Rafa may not be at full speed, could leave an opening. Djokovic nearly took advantage of that today.
So what happens if he loses to Fed in the finals? And we already now know that in the semifinal matchup, for the 3rd straight time facing Djokovic on clay this season, Nadal dropped a set. We also now know that Djokovic took him to tiebreakers in the other 2 sets that Nadal won including taking the third set to an 11-9 tiebreak score. This is the kind of thing that starts to embolden the rest of the field into not necessarily believing it's over before it starts when they play Nadal on clay.
That kind of thinking among the contenders along with some unlucky bounces (which clay is known for) could make all the difference at Roland Garros next week. I'm not saying that Nadal is going to lose. What I am saying is that part of Nadal's edge on clay is the mental edge that comes with players believing that he is unbeatable.
If the field were to see Roger win tomorrow combined with having already witnessed the level of stress that Djokovic has been able to apply to Nadal in their three clay matches so far this year, that thinking among the field (and the edge that comes with it) could start to change.
To all of those readers who would scoff at the idea of Rafa losing Roland Garros, keep two things in mind. Firstly, Nadal isn't going to win the French forever. And, secondly, whenever he does finally lose (provided that it's not due to an injury), it will most likely be unexpected. So my point is that the unexpected has as good of a chance of happening now as any...especially if Rafa no longer seems invincible to the field.