By Tom Perrotta

Head of the Class
Rafael Nadal: So far, Nadal seems quite comfortable with his no. 1 ranking. On court, he’s all business (he hasn’t lost a set). Off court, he speaks confidently and says he’s healthy. One more fabulous week and he polishes off the best summer in tennis in almost 40 years.

Skipped a Grade
Kei Nishikori: The 18-year-old Nishikori, the youngest man remaining in the men’s draw, took out no. 4 seed David Ferrer in five sets. He’ll be the underdog in the young man’s quarter, where Stanislas Wawrinka, 23, is the veteran.

Caroline Wozniacki: The 18-year-old from Denmark couldn't close out Jelena Jankovic after winning the first set, but she has had a fine season so far (43-15 record, two titles) and reached the fourth round of a major for the second time this year (she did the same at the Australian Open). Wozniacki’s strengths are her two-handed backhand, her speed, and her determination. We'll be seeing a lot of her in the years to come.

Honor Roll
Roger Federer: So far, so good for the four-time defending champion. He hasn’t lost a set in four matches and he couldn’t ask for an easier draw leading up to the semifinals. Does he have the confidence to beat Novak Djokovic and Rafael Nadal on back-to-back days? Looks like we’re going to find out.

The Sisters Williams: Serena has lost 10 games through three rounds; Venus has lost 11. They have been the two best players in the draw by far, with Venus, by the slimmest margin, looking slightly better than her sister. Venus played exceptionally well here last year: Her semifinal against Justine Henin was one of the best matches of the season. At this point, it seems that one of them will win the title (though they’ve fooled us before). What a shame that they have to play each other in the quarterfinals rather than the final.

Novak Djokovic: Djokovic isn’t clowning around this year. Can he get one more victory than last year, when he lost to Federer in the final?

Sam Querrey: Querrey’s best showing a major tournament began with a drubbing of Tomas Berdych, progressed to a solid second round victory, and yesterday culminated in a poised upset of Ivo Karlovic, the hard-serving no. 14 seed. Querrey’s tournament ends on Monday when he plays Nadal, but it’s been a good run.

Agnieszka Radwanska: She’s small, doesn’t hit the ball very hard, and can’t serve her way out of trouble. But what Radwanska lacks in power she makes up in polish. She’ll put her clean strokes and smart tactics up against Venus Williams in the fourth round.

Amelie Mauresmo: Great to see her healthy again. Does she have another major in her?

Gilles Muller: Remember him? The man who stole Andy Roddick's mojo at the 2005 U.S. Open is back and looking for more upsets. Muller nearly lost in the first round of the qualifying tournament, where he came within two points of defeat against Lamine Ouahab of Algeria, ranked. No. 254 in the world, before prevailing 6-7(11), 7-6(6), 7-5. A few days later he defeats Tommy Haas in the second round after losing the first two sets, 2-6, 2-6, 7-6(5), 6-3, 6-3. Then he repeats the performance in the third round, beating Nicolas Almagro, 6-7(3), 3-6, 7-6(5), 7-6(6), 7-5 (he was two points from defeat in the fourth set).

The other Anna: The last few years haven’t been kind to Anna-Lena Groenefeld, the former no. 14 player in the world. She had a bad break-up with her former coach, Rafael Font de Mora, who, Groenefeld says, later taunted her during matches and gave advice to her opponents. She put on weight, lost her confidence, and finished last season ranked no. 204 in the world (for more, click here). Groenefeld has a record of 36-4 this season and a date against Dinara Safina in the fourth round.

Mardy Fish: Fish moves into the fourth round at the U.S. Open for the first time in his career after a convincing victory over buddy James Blake.

Sybille Bammer: The 28-year-old mother reaches the quarterfinals by taking out Marion Bartoli in the fourth round.

A’s and B’s
Gael Monfils: So much talent. So fun to watch. Such a good dancer. So close to injuring himself on every slide along the baselines of Flushing. Roger Rasheed, we all hope you can do for Monfils what no coach before has been able to do. As he is, Monfils could win a major title (though he’d need a lot of luck along the way). If he ever learns to control his body, attack more, defend less, cut down on all the slides, splits, and hand stands that have caused him so many injuries in the past, look out. His fourth round match against Mardy Fish ought to be great theater: the attacker versus the defender. The winner plays Nadal (sorry, Sam!).

Stan the Man: Stanislas Wawrinka, who won a gold medal in doubles with a guy named Federer, isn’t suffering from an Olympic hangover. Wawrinka recovered from two-sets down on a humid afternoon to defeat Flavio Cippolla and move into the fourth round.

Dinara Safina: Throw out Safina’s clunker of a gold medal match in Beijing (17 double faults) and she might be the favorite here. We’ll see if her nerves can remain as strong as her arms and legs for another week.

Andy Roddick: He showed his toughness in the second round against Ernests Gulbis. We're looking forward to a blockbuster quarterfinal against Novak Djokovic on Thursday evening.

A for Effort
Lindsay Davenport: Davenport hasn’t played a lot of singles this year and she can’t seem to stay healthy, but she couldn’t miss the U.S. Open, which she had played for 16 consecutive seasons before missing last year’s when she gave birth to her first child. She’s playing doubles with Daniela Hantuchova, so what might be her last U.S. Open could still end with a title.

Ryler DeHeart: For about 15 minutes in week one, DeHeart, the 24-year-old former Illinois standout, was the best tennis player in the world, good enough to win 13 out of 15 points against Rafael Nadal, most of them sizzling winners or unreturnable volleys. DeHeart returned to earth before long, but he did himself, and college tennis, proud.

Needs a Tutor
Ana Ivanovic: The good news - Ivanovic’s thumb injury is on the mend. Still, even given her limited play, she was expected to beat qualifier Julie Coin. Let’s hope Ivanovic gets back to her old ways, and then builds from there, before the season ends.

Mr. Muscles: There was Andy Murray, flexing his right bicep (as he did at Wimbledon) after another comeback from a two-set deficit. Murray ought to be proud of his fitness, which has improved greatly in the last year or so. Now, if he could only learn how to dispose of early-round opponents easily so he can use his strength on the best men in the draw. If Murray’s going to be a consistent champion some day, he has to conserve energy in week one.

Excuses, Excuses
Fabrice Santoro: The Magician was bothered by Andy Roddick’s accidental body serve, at 140 mph, on the second-to-last point of their first-round match, so much so that he conceded the next point. I thought his concession was fitting—if you can’t return serve, step aside for someone who can. I'm all for gentlemanly behavior on the court, but not charity.

Talking out of Turn
Marat Safin: Lost the fourth set of his second round match at love as was fined $2,000 for an on-court tirade after a foot fault call in his first-round match (it came on a second serve at 30-30 with Safin serving at 4-5; he lost the set 6-4). The Russian would have made a great attorney, as this closing argument attests.

"It's impossible, and it shouldn't be--it's unwritten rule--anybody who plays tennis in their life, in a career, it's difficult and it's almost impossible to make a foot fault on a second serve, and especially in the important moments you shouldn't call it. If you are doing a foot fault on a second serve, first of all you need to get a warning. So basically you're making foot fault? Just watch out; next time I'm going to call you. This is how it should be. So I don't think I'm missing some rules in tennis. I think the people in tennis are missing some rules. It's really, really disappointing on the fourth set because foot fault on the second serve and you're facing set point. So I think I have the point here, and the people, they should, they should do something about it. I understand there are tons of people, officials are telling them about the rules. But sorry. Who are the players? If you ask anybody in the locker room, they will tell you the same thing. It's wrong. I think the officials, they should change something, because they don't understand it."

Caught Cutting Class
Czech Talent: Are there two more disappointing pros than Nicole Vaidisova, who lost in the second round, and Tomas Berdych, who won a mere seven games against Sam Querrey in the first round? Look at these two powerfully-built athletes and you have to be convinced, once and for all, that the mind is the most important muscle in tennis.

Tommy Haas: Haas squandered a two-set lead against Gilles Muller and then let his temper get the better of him when he refused to shake the chair umpire's hand. Haas had argued an ace call in the final game; Hawk-Eye was not available on his court.

Expelled
Svetlana Kuznetsova: Maybe she has been eating too many meals with Berdych and Vaidisova?

Rude fans: One jerk taunted Michael Llodra so much during his match against Andy Murray that security had to step in.

The J-Block: It's fine to assemble and cheer on your man, but they went overboard in the Fish-Blake match, even drawing a warning from the chair umpire. It might be time for this show to close.