Tough call for me general. Rafa almost always shows up at a fairly high level against Roger. Roger's level varies more, especially in the last few years. He can be sublime on occasion, good level more often, and sometimes in self destruct mode. It's not clay, so Rafa doesn't have a big advantage. We don't know if it will be played indoors or not, but there is rain and cool weather forecast for Friday.
I think the courts are about the same, but the balls are different, lighter and go through the court faster, which might favor Federer in that it is easier for him to generate winners without as much risk.
He's playing pretty solidly this tournament, especially on serve, only broken twice, losing only one set. The backhand looks good, he's more aggressive, but controlled, sneaking in when he has hit the proper approach shot. However, I was a bit surprised he didn't close it out in 3 sets today vs. Murray as it was on his racquet and he served well the entire match previous to the 5-4 game and the tiebreaker. Seems like he got a bit tight for some reason. And Murray was good enough to seize the opportunity and snatch the set. That won't do against Nadal. Federer can't play a 40 error game vs. Nadal. I would say he needs to hit no more than 5-7 per set, and 10-15 winners/set to do well against Nadal. But that's easier said than done. Nadal forces his opponents to attempt riskier shots and make more errors with his court coverage and defense. Today against Andy, Roger ventured to the net 66 times and won 47 points (74%), quite good vs. someone who returns and hits passing shots like Murray. He won 147 total points vs. 121 (+26) for Murray, and his 2nd serve win percentage was excellent, winning 64% vs. Murray's 49%. Against Tsonga, he was 34 for 41 (84%) at the net, won 69% of his second serves, and won 100 points vs 72 for Tsonga (+28). So Federer was pretty consistent in the 2 matches. If he can play similarly or slightly better, I think he will have a very good chance against Nadal.
Nadal has played well enough to win, but nothing special in the last two matches. Though his draw started out looking tough, it opened up a bit, when Tomic retired and Del Potro lost early. He's faced 3 higher seeded players - #25 Monfils who didn't play well, #22 Dimitrov who played pretty well, and #16 Nishikori who also played well, but no top 10 player. In those latter two matches, I don't think Nadal played all that well, and maybe the hand blister is bothering him, but still managed to win. I think he definitely needs to play better against Federer.
So one question for me, is did Nadal get enough from those matches against those players. He might have trouble raising his level if Federer plays well. But it is best of 5, so he has time to get into the match. I didn't like his forehand today against Dimitrov. He was very inconsistent with it. He's also slicing a lot. Maybe that's due to the hand. The slice won't bother Federer. He needs to be able to get his forehand extreme topspin going to Federer's backhand and the down the line drive shot accurately placed. He also needs to be in the court more and get more depth. If he hits short against this Federer, I think he'll get roasted. Federer is looking to come in on anything short and put it away. But we know Rafa. If he can get that forehand working, Federer will have trouble if the ball gets high and deep to his backhand.
So as in any match, it depends on what game they bring to the table. Federer hasn't beaten Nadal in 2 attempts at the AO, but like they say, each match is different. In general, if both men are pretty much on their game, if the conditions are such that the ball is staying lower, then it favors Federer, otherwise Nadal.
Motivation? Nadal is looking to tie Sampras, complete a second career slam, and get closer to Federer. Federer, well, he's looking for good results following last year's mediocre season. He already has good results by making it to the semifinal beating both Tsonga and Murray. Tough draw? maybe, but what doesn't kill you, makes you stronger, unless you are too exhausted. He's 32 going on 33. Can he recover from an hour longer match against Murray then it had to be? I don't know. I'm sure the Swiss Maestro would like that 5th AO and 18th slam to try and pull a little more away from Clay Warrior.
You have to figure that the winner of this match has a great chance to win the Final, probably Rafa a bit more than Roger due to Berdych being fairly competitive with Federer the past few years. On the other hand, if Wawrinka makes it through unscathed his confidence would have to be sky high, and he could pull off another big upset. One thing at a time. Let's see who makes it to the Final.
At this moment, if I were playing it safe and had to choose, I'd probably choose Rafa and Stan based on the recent H2H. But H2H isn't everything, and these matches have been won by the other guys enough to know that their matches are not a given.
I'll probably wait till near game time to attempt a final prediction Nadal - Federer. I'll take Stan in the other one as of now.
Respectfully,
masterclass