Surveying the obscure survivors

NEW YORK -- There's no making head or tail of the women's field at the U.S. Open, but this much we know: There will be a virtual unknown in the quarterfinals, a surprise semifinalist and a dark-horse finalist. The third quarter of the draw has fallen apart -- or at least fallen open -- guaranteeing there will be some unexpected names late in the second week.

First to go was reigning Wimbledon champion Petra Kvitova, followed quickly by French Open winner Li Na. The potentially dangerous Agnieszka Radwanska and Marion Bartoli were next to fall, while 2009 U.S. Open semifinalist Yanina Wickmayer retired with injury. (Paying attention? These are the known players.) That left Lucie Safarova as the only solid name in that section, so what does she do? Goes out and loses 6-0, 6-1.

The carnage reached its height when Maria Sharapova went out in the third round to Flavia Pennetta. Though the canny Italian was always a threat to defeat the biggest name in this part of the draw, the upset does mean there will be a first-time semifinalist next week. Pennetta is the only one of the four players left in the third quarter to have ever reached a Grand Slam quarterfinal, and Shuai Peng is the only other player of the four to have reached the fourth round.

Given their relative anonymity, here's a fact or two about each:

Monica Niculescu: She's double-fisted on both sides. No, wait, she hits with one hand. No, wait … the Romanian is always changing up her strokes, hitting a conventional forehand and single-handed backhand when reaching for the ball and going to two hands on both wings when she wants to hit a strong drive.

Angelique Kerber: The 23-year-old German was recently invited to train with Andrea Petkovic, who predicts her countrywoman's ranking will be in the 20s in a few months.

Shuai Peng: China's first breakout player, she was described by Clijsters as a potential "top three" player after Peng defeated Clijsters in 2005. Although Peng hasn't quite made it that big, she is currently at a career high of No. 14.

Flavia Pennetta: She was the first Italian woman to be ranked in the top 10 and played one of the most memorable women's matches at the U.S. Open in defeating a crying, screaming, bandage-tearing Vera Zvonareva in a pounding fourth-round encounter two years ago.

Familiar hurdles for Murray, Nadal

After surviving five sets in his previous round, Andy Murray faces his mum's heartthrob, Feliciano Lopez. Still, it won't be as bad as Wimbledon, when much to Murray's embarrassment, the two faced off during the peak of publicity given to Judy Murray's nickname of "Deliciano" for Lopez. Murray's quick-witted mother, once the top coach in Scotland, has been more low-key on this side of the pond, but with no less of a roving eye. She tweeted earlier in the week: "Dish of the Day on Grandstand right now at USO … Jesse Huta Galung v James Blake."

Luckily for Murray, neither of them are left in the draw.

Apart from all that, however, Murray has had little trouble with Lopez in the past, winning all five of their previous encounters. But the Spaniard has been playing some of his best tennis this season, and his stylish attacking game should make for an attractive contest with Murray.

The same is expected for the meeting between Rafael Nadal and David Nalbandian. Nadal is still working his way into form, and Nalbandian's high-quality game would normally be a serious threat -- the only question is whether the Argentine has too little steam after so many injuries during the past couple of years. They've split their four previous meetings, with Nadal winning the past two in tough three-setters. The two are friendly off the court, piling on to the couch with a bunch of other players to watch the Barcelona versus Real Madrid soccer game in the players' lounge in Cincinnati three weeks ago.

Quiet champion

2009 U.S. Open champion Juan Martin del Potro is back after missing last year while recovering from wrist surgery. He has the game to win the U.S. Open, clearly, but does he have the confidence? That seemed to be the missing element in his losses (but otherwise good performances) against Novak Djokovic at the French Open and Nadal at Wimbledon; a rather meek loss to Federer in Cincinnati means there hasn't been much talk about the Argentine as a potential contender.

He was also playing down his own chances coming into the tournament, another sign he's not quite sure of himself yet. "Now I'm in the third round, so I need to improve; I need to be more confidence with my serves and forehands," said del Potro, who faces Gilles Simon next.

But that could come in a hurry if he starts to feel his game rising or gets pumped up after winning a tough battle, making him worth keeping an eye on.

American dreams

A stirring five-set win has put Donald Young into the U.S. Open spotlight and rehabilitated his reputation after a spat with the USTA earlier this year. Then there was a rebuke by Patrick McEnroe for Young's tweet containing profane criticism of the USTA; after Young's win Friday, McEnroe tweeted, "In tennis terms Donald Young became a man today."

"That's great for someone of his status to say something like that and really feel that," said Young. "It's great. I'm happy he feels that way."

Young also cited some inspiration from Pete Sampras. "We practiced together a couple times. Played a game of 21. He beat me. He let me know that wasn't good. And he talked and called me a little princess and everything," Young recalled, smiling. "When he was driving off, he was like, 'I expect to hear some big things from you.' That made me sit back like, 'Wow, Pete Sampras just said he expects me to do some big things.' That gave me a lot of confidence and pushed me to work even harder."

With a manageable opponent, Juan Ignacio Chela, next up in the third round, Young has a chance to build on the victory.

Another player on an unexpected surge is Alex Bogomolov Jr., who will face his "dream crusher," John Isner, in the third round.

"I played him third round in the [Miami Masters]; he beat me," said Bogomolov. Then I played him in quarterfinals of Newport; he beat me. So it's been sort of anytime I'm close to making a really big run, he's kind of stood in the way."

The trend won't be easy to reverse, with Isner saying his confidence is at a high following a win at his home tournament last week and good runs earlier this summer.

Kamakshi Tandon is a freelance tennis writer for ESPN.com.