Flushing Meadows, NY (My Sportsbook) - Young American Melanie Oudin stunned former runner-up Elena Dementieva and Kazakhstan's Yaroslava Shvedova upended last year's runner-up Jelena Jankovic in second-round action Thursday at the U.S. Open. World No. 1 Dinara Safina managed to avoid an upset to reach the third round here.

The 17-year-old Oudin shocked the fourth-seeded Dementieva 5-7, 6-4, 6-3 in a high-quality second-round affair at Arthur Ashe Stadium.

Dementieva barely snuck out the first set against the gritty Oudin, who simply played better tennis than her Russian counterpart on Day 4.

The rising Oudin pulled out the second set with a service break and then went on to claim the third despite being hampered by a sore left leg.

Oudin headed into the match with a wrap on her left thigh, and had the leg re- wrapped early in the final set.

The American broke Dementieva to grab a 2-0 lead in the third and was leading 3-1 in the set when she broke down in tears on the court after experiencing some sharp pain in her leg in the fifth game. Dementieva broke to win that game, but a gutsy Oudin broke right back for a 4-2 advantage, then held for a commanding 5-2 lead, and then held in the ninth game of the stanza to record the biggest win of her blossoming career.

The Marietta, Georgia native Oudin converted on a third match point when Dementieva was unable to return a big serve from the American after 2 hours, 45 minutes of play. The Russian saved a pair of match points with a backhand winner and forehand volley winner.

Dementieva wound up with nine double faults and had her suspect serve broken seven times. Oudin moved on despite being broken six times and tallying 44 unforced errors.

The reigning Olympic gold medalist Dementieva is a two-time major runner-up, including a trip into the U.S. Open final back in 2004. She entered this particular fortnight as the hottest player on the women's tour, having won the US Open Series points title heading into this great American sporting event.

Meanwhile, the 21-year-old Shvedova, ranked 55th in the world, knocked out the fifth-seeded Jankovic in 6-3, 6-7 (4-7), 7-6 (8-6) fashion, also at Ashe Stadium.

Jankovic broke Shvedova to level the third and final set at 6-6 and force a deciding tiebreak. But in the extra session, the Serbian star blew a pair of match points, as Shvedova knotted the tiebreak at 6-all. Two points later, the Moscow native converted on her first match point with a bout-ending ace.

Shvedova pulled off the upset in 2 hours, 40 minutes with the help of eight service breaks, compared to six for Jankovic, who lost to Serena Williams in last year's finale here.

The French Open and Australian Open runner-up Safina dropped the first set against German Kristina Barrois before charging back for a 6-7 (5-7), 6-2, 6-3 decision at the Billie Jean King USTA National Tennis Center.

Safina advanced in 2 hours, 13 minutes despite piling up 15 double faults and 38 unforced errors. Fortunately for the big Russian, she was able to break Barrois' weak serve on eight occasions.

The 23-year-old Safina also needed all three sets to sneak past Aussie teenager Olivia Rogowska here on Tuesday.

Safina's third-round opponent will be a another non-seed, Czech Petra Kvitova, an easy 6-1, 6-3 victor against Italian Tathiana Garbin.

Ninth-seeded Dane Caroline Wozniacki stayed hot with a 6-1, 6-0 dismantling of Croat Petra Martic. The 19-year-old Wozniacki is fresh off her hardcourt title in New Haven last week.

Up next for Wozniacki will be rising Romanian Sorana Cirstea.

Thirteenth-seeded Russian Nadia Petrova moved on with a 6-4, 7-6 (7-3) victory over Frenchwoman Julie Coin, while 21st-seeded Chinese Zheng Jie came back to best France's Alize Cornet 1-6, 6-3, 6-3 and a 24th-seeded Cirstea held off Canadian Stephanie Dubois 6-4, 5-7, 6-4.

Mild upsets came when Italian Sara Errani erased 19th-seeded struggling Swiss Patty Schnyder 7-5, 6-2 and Argentine Gisela Dulko drubbed 30th-seeded Ukrainian Alona Bondarenko 6-4, 6-0.

In other second-round play, Ukrainian Kateryna Bondarenko blitzed American Shenay Perry 6-1, 6-1 and Belgian Yanina Wickmayer downed Chinese Peng Shuai 2-6, 6-1, 6-4.

This year's U.S. Open champion will collect at least $1.6 million.