One of his two victories on clay against the world No. 1 came in the Spanish capital, where a higher altitude means the ball travels significantly faster through the air. A boost for Federer.
Certainly Federer was thinking positively heading in, trying to forget their last meeting, a 6-3, 6-2 drubbing at the Sony Ericsson Open this spring.
"I think these are quicker conditions than Miami," Federer said.
And things went better than in Miami, although ultimately not good enough for the 16-time Grand Slam champion, who fell for the 11th time in 13 tries on dirt.
Nadal prevailed 5-7, 6-1, 6-3 in an absorbing two-and-a-half-hour semifinal.
Here are three takeaways from Saturday's duel.
Federer can take it to Nadal on clay
Early in the first set it was a case of deja vu.
When presented with seemingly easy forehands, Federer missed -- and a few of the errors were ugly. This wasn't the Swiss just having a bad start, but the result of Nadal's presence on the other side of the net. Federer feels like he has to be perfect to put away Nadal in a rally, and surely he's not the only one. Both players began the match sluggishly.
But the complexion of the set changed when Federer, trailing 4-2, began with a successful serve and volley. He held comfortably and then went on the attack, propelled by the backhand.
Twice he crunched backhand returns -- waiting for the ball on that side as Nadal, as usual, targeted it -- and short, wicked slices to get Nadal out of position, before applying the knockout punch. It was reminiscent of the tactics he uses against the likes of taller, less mobile foes such as quarterfinal victim Robin Soderling and Tomas Berdych.
As he loosened up, suddenly the forehand began to work, and Federer was at his free-flowing best.
The final six games of the set produced fine tennis, with Nadal upping his game, too.
Perhaps the shot of the match was Federer hitting a backhand pass off a curled forehand approach, reminiscent of the one he produced against Nadal in the 2008 Wimbledon final to stave off a match point. But this time he sent it crosscourt.
Don't let the score of the final two sets fool you, either. Federer wasn't blown away. He had break points in each of Nadal's service games in the second, the opening break chance of the third and another opportunity in the final game of the encounter.
Nadal was there for the taking, only exhibiting his best in patches. While Federer often dictated proceedings, Nadal was too often passive in rallies. There weren't, for instance, many forehands down the line, his favorite shot.
Chance missed for Federer.
If they meet in the semifinals of next week's Rome Masters -- they're in the same half -- conditions won't be on Federer's side.
Fed is getting irritable
Is Federer getting more agitated as he nears 30? Maybe.
He hasn't been in the best of moods on court, clashing with the chair umpire in a third-round win over Xavier Malisse.
No fewer than four times did Federer show his displeasure with Mohamed Lahyani on Saturday. But he really had no case.
Federer wanted a point replayed at the end of the fourth game when a ball person, he suggested, began to move before the point ended. Nadal had the point won, and it's questionable whether the movement made any difference.
Worse, Federer didn't accept Lahyani's judgment when he was broken to start the second. A big Nadal crosscourt forehand appeared to hit the line, and no out call came. Federer asked Lahyani to check the mark, and he confirmed the ball was good.
When Federer crossed the net to receive serve, he seemingly wanted Lahyani to check the mark again.
An umpire doesn't want to get on the bad side of Fed, and in the last game, with Nadal staring at a break point, he issued a warning to Nadal for taking too much time.
Was that to appease Fed? Fed and Lahyani shook hands when it was over. Yes, it was a good handshake.
Federer began to flex his shoulder midway in the third set, possibly another source of angst.
Rafa shows emotional side
Some would think Rafa, with all his muscles and warrior-like mentality, would be the last guy to cry on court.
In reality, he's pretty sensitive. He broke down in the locker room after losing the 2007 Wimbledon final to Federer, for instance.
Nadal wiped away tears before his match Saturday after a tribute to Spanish golf legend Seve Ballesteros, who died from complications of a cancerous brain tumor Saturday at the age of 54.
Nonetheless, it was a happy ending on court for Rafael Nadal.