Li Na has been one of the biggest breakout stories in 2011.
The first week of the 2011 US Open has been similar to the other three majors this season. The top men have been advancing, while there has been a slew of upsets on the women's side.
Petra Kvitova and Li Na have had break out results on the big stage this year but there has not been a first-time grand slam finalist in the men's game.
It would be a pretty big surprise if there was a first time men's finalist in this major (US Open Series winner Mardy Fish might have the only chance to do that). The women's field could easily see two first time slam finalists.
Here is a list of potential breakout players to watch in the second week of the season's final major.
Big-serving American John Isner has really been coming into his own in the summer hardcourt season. His forehand has been much improved, giving him a complimentary weapon to one of the best serves in tennis.
Isner has always been a player that other guys have not wanted to play because there is almost no rhythm in his matches. Becoming more versatile will lead to even more fear from his opponents and better results.
That being said, it would still be a surprise to see Isner playing a week from now. He would likely have to take out 2009 US Open champion Juan Martin del Potro, world No. 5 David Ferrer and three-time grand slam finalist Andy Murray in succession to get there.
Young German Andrea Petkovic got herself on the map last season at Flushing Meadows by reaching the second week of a major for the first time.
With all of the upsets thus far, Petkovic finds herself as one of the few top ten women remaining in the field. If she was 100% fully healthy, people would probably be talking about her as a top contender for the title.
The German has reached two quarterfinals in Grand Slams this year and is looking to make the next step. She is at her best on a hardcourt and has blossomed into one of the most mentally strong players out there.
Petkovic has also seemed to figure out how to play effectively even with a slight knee injury. Look for her to make a serious run at the US Open Championship.
It's not often that you would be thinking about a breakout performance by a World No. 1 player. Caroline Wozniacki is in an almost unprecedented situation.
While Wozniacki has plenty of titles on the WTA tour (18 to be exact), she has not yet won a Grand Slam tournament. Her closest result came two years ago in New York, losing to Kim Clijsters in the championship match.
Winning the 2011 US Open would solidify Wozniacki as the No. 1 player, as almost no one gives her credit for that rank due to her struggles on the big stage.
The Dane has been ranked No. 1 for 46 weeks, but has been under pressure for quite some time now to win a major. A win here would silence her critics and most likely vault her into a great career.
Talented American Donald Young just had the biggest victory of his career yesterday, knocking off 14th-seeded Stanislas Wawrinka in a fifth-set tiebreaker in the second round of the US Open.
The win could mean big things for Young in the near future. Tennis aficionados have been waiting for him to make his move for quite some time now.
In order to make the second week, Young will have to get through veteran Juan Ignacio Chela. Chela is more of a clay-court specialist, and the American has a good chance to win that match as long as he avoids a mental letdown.
American tennis has been looking for someone to step up, and Young might be the guy that can bring it back on the map. He's really improved his fitness and is starting to put everything together.
The Chinese have already been able to celebrate the coming out party of one of their own in 2011. Second-ranked Chinese woman Peng Shuai hasn't had quite the results as Li, but is the No. 13 seed at the US Open.
Peng has had consistent results in 2011, but is looking to make the kind of move Li did at the first two majors this year. She is already through to the fourth round, and is in a great section of the draw after Maria Sharapova was taken out yesterday.
The Chinese woman has to be the favorite to get through to the semifinals of her section now. That would likely land her a showdown with 2010 finalist and No. 2 seed Vera Zvonareva.