The 2013 U.S. Open has reached the third round of action, presenting numerous under-the-radar players with the opportunity to defeat high-profile opponents. As always seems to be the case, we saw numerous players take advantage of that chance and move one step closer to tennis immortality.
The question is, which players pulled out the most impressive upsets?
Certain players have gone from unranked to intimidating, earning multiple victories over ranked opponents en route to a fourth-round appearance. Others have earned a seeding but remain long shots to win big.
After their performance in the third round, we may need to rethink that evaluation.
No. 21 Simona Halep def. No. 14 Maria Kirilenko
Score: 6-1, 6-0
Halep's WTA Rank: No. 19
Kirilenko's WTA Rank: No. 17
This isn't a groundbreaking upset, as Simona Halep is only two spots below Maria Kirilenko in the WTA rankings. With that being said, Kirilenko is one of the better players in the world, experiencing success at every Grand Slam event in singles and doubles play.
Halep ended up dismantling her, 6-1, 6-0.
Halep, 21, was one of the best junior players in the world but had never reached the fourth round at a Grand Slam. She now punches her ticket into the fourth round at the U.S. Open, where she'll face unseeded Flavia Pennetta.
In turn, Halep has gone from an underdog to the player who's favored to reach the quarterfinals. Should she reach that point, the top-two seeded players whom she could meet are No. 6 Caroline Wozniacki and No. 10 Roberta Vinci.
It's safe to say Halep has a fighting chance at reaching the semifinals. Who saw that coming?
Flavia Pennetta def. 27 Svetlana Kuznetsova
Score: 7-5, 6-1
Kuznetsova's WTA Rank: 29
Pennetta's WTA Rank: 83
Flavia Pennetta continued her red-hot play, defeating No. 27 Svetlana Kuznetsova, 7-5, 6-1. Kuznetsova's ranking may suggest she's not an elite competitor, but the Russian star won the 2004 U.S. Open and 2009 French Open.
It's yet another notch in the belt for Pennetta.
She has reached the quarterfinals in three separate U.S. Open appearances. In 2013, she's now one win away from making it four quarterfinals appearances and earning a true opportunity to win it all.
Best of all? She's doing it as an unseeded player who has already brought down some of the biggest names in women's tennis.
Pennetta defeated No. 4 Sara Errani in the second round and will now face No. 21 Simona Halep with a berth in the quarterfinals on the line. From there, Pennetta may just end up as an unseeded title contender.
This is why we love the U.S. Open.
Alison Riske def. No. 7 Petra Kvitova
Score: 6-3, 6-0
Kvitova's WTA Rank: 10
Riske's WTA Rank: 81
Petra Kvitova, 23, is currently ranked No. 10 in the world with a seeding of No. 7 in the 2013 U.S. Open. She won the 2011 Wimbledon and the 2011 WTA Tour Championships, earning a reputation as one of the best up-and-coming players in the world.
At the 2013 U.S. Open, her rise was put on hold as another 23-year-old took her shot at glory: American wild card Alison Riske.
Riske didn't just beat Kvitova; she dominated her, winning 6-3, 6-0. She was close to perfect in the second set, capitalizing on Kvitova feeling under-the-weather by hitting the type of shots that forced her opponent to fatigue quickly.
It was a methodical and downright impressive win for the young American.
While fellow Americans Jamie Hampton and Sloane Stephens steal headlines, Riske is the one with the greatest opportunity to reach the quarterfinals. Stephens will face Serena Williams next, Hampton has been eliminated, and Riske is facing fellow unseeded player Daniela Hantuchova.
From unknown to the fourth round, Riske is on the cusp of stardom.