Matt Cronin's Day 10 Analysis

1-RAFAEL NADAL V. MARDY FISH

Fish was adamant in saying that his old-school attacking game can threaten Nadal, and maybe it can on a great day. But what cannot be dismissed is that Nadal is 4-0 lifetime against Fish and has never lost any of the 10 sets they've played, and two matches were played on grass and the other two on hardcourts.

So while a zoning Fish with a raucous crowd behind him can do damage, the world's top player won't be walking on court shaking in his shoes. He must have a good idea as to how to return Fish's serves proficiently enough, how to pass him when he's climbing all over the net, how to exploit the American's weaker forehand.

Nadal did not play very well in his four-set win over Sam Querrey, and Fish played great in throttling Gael Monfils. That's the major positive that Fish can take into this match -- that maybe he'll continue to kiss the corners, while Nadal will be content hugging the middle of the court.

This is a pretty simple call. Will Nadal's excellent returning, mind-boggling passing shots and tireless play from the backcourt be enough to hook the streaking Fish, or can Mardy serve and volley his way to the year's biggest upset? The answer is pretty clear: Nadal will lose his way for a set and a half, but Mardy is due to come back to earth and will fall in four hard-fought sets.

6-ANDY MURRAY V. JUAN MARTIN DEL POTRO

There seems to be a mini-blood feud boiling here, as back in May at Rome, Andy Murray accused the 19-year-old Argentine of insulting his mother, Judy, during a heated match. "I haven't spoken to him since, so whether there is unfinished business or not, it's just another tennis match to me,” Murray said. “Whether I like Del Potro or not does not really make any difference. I wasn't great friends with him before. I don't need to be friends with him now.”

Murray said the incident doesn't bother him any more, but Del Potro's form just might. The tall and deceptively fast Argentine has won 23 straight matches and seems to have all the makings of a top-5 player to be. He owns a big serve and crushing forehand and is competing very well, despite having played a tremendous amount during the past two months.

But Murray is in better form, is a smart player and knows how to blunt big servers. He was near perfect in crushing Stan Wawrinka and realizes that this should by all rights be his breakout Slam. His first serve is to be feared when he's in the zone, his groundstrokes are thoughtful, and his return is world-class.

Del Porto will go straight at him and will be difficult to break, but the Argentine hasn't faced such an intelligent competitor yet. Del Potro is sure to be pumped and produce plenty of fireworks for a set and a half, but Murray will get into his head and come through in four sets.

6-DINARA SAFINA V. 16-FLAVIA PENNETTA

Going into their final-round clash in LA about six weeks ago, I tried to conceive of a way that Pennetta could take down Safina, and I could only think of one: if the Russian grew tired and erratic and the Italian played super steady and with force. That didn't occur, and Pennetta was clearly out-classed in the match.

Safina is a superior player when she's on, so much of the same scenario will occur here: will Safina, who said she nearly pulled out of her previous contest because she's fried after a long summer, give in to her tired legs and mind, or will she finally see the goal line in sight and unleash her incredibly impressive game?

The thought here is that the Russian will, because after two days of rest and re-focus, she should be ready to let it all hang out. When she does, she serves and strokes the ball too firmly for Pennetta, who has done all she could this year to push herself to her limits but may have topped out in ability. She can certainly out-steady Safina if the Russian gets in a funk, is well conditioned and is a terrific fighter, but Dinara will convince herself that the only way to end her summer on a positive note is to go deeper here and win in straight sets. She has to crave a clash with a Williams sister in the semis, and she'll get one.