In these hot conditions, Nadal finds it easy to push Murray around and from there, it's over. I've said this early in the tournament, for all of Andy's terrific defense, his counter-punching is relatively ineffective on clay. Compare what Novak does with the ball when he tracks it down to what Andy does (again, strictly on clay). He seldom reverses rallies around after being dictated, at least against Nadal (which is uncharacteristic when you compare how he plays on other surfaces). So in general, he's forced to be aggressive, something he's not comfortable with on this surface. That's why I don't really think he still knows how to approach playing on clay.
Murray's comments kinda reveal how difficult this match-up is for him on clay, especially in these conditions:
"Today he was hitting extremely hard, extremely heavy, returning well, and was hitting it well on the run,"
"But, again, you can go out there with all the tactics in the world, but when he's hitting the ball like that, it's very difficult to hit the ball where you want to."
"His shot was bouncing incredibly high. It was very difficult to do much with the ball," "His forehand, especially with the conditions the way they were today, was incredibly hard to control.
"Then when I did have the opportunity, I wanted to make a winner or make him run too much, trying to hit too close to the lines, and ended up making a lot of mistakes."
The last couple of quotes sum up this match (other than Murray playing poorly). Nadal's forehand pushes Murray back on clay, whereas on other surfaces he's able to step inside and take it early. And when Murray did try to take it early, he messed up. That's the match in a nutshell.
