Two young-gun American mixed doubles teams pulled off improbable upsets at the US Open on Saturday to advance to the quarterfinals.

Melanie Oudin and Jack Sock stunned top seeds and defending champions Liezel Huber and Bob Bryan 2-6, 6-3, (10-6). It was an impressive comeback for the teenage combination, as Bryan has won seven mixed doubles titles, including four at Flushing Meadows, while Huber has claimed two trophies.

With the win, Oudin avenged a second-round loss to Huber and Bryan at last year’s Open, when she partnered with Ryan Harrison. In the final eight, Oudin and Sock will face the winner of Daniela Hantuchova-Mark Knowles and Barbora Zahlavova Strycova-Philipp Petzschner.

Irina Falconi and Steve Johnson also gave an inspiring performance, knocking out No. 2 seeds Katarina Srebotnik and Daniel Nestor 6-4, 3-6, (10-8).

Though they won five fewer points than Srebotnik and Nestor, the Americans squeaked out the victory in a nail biting champion’s tie-break. Srebotnik and Nestor were looking to win their second mixed doubles title of the season, after triumphing at the Australian Open. Falconi and Johnson advance to play Lucie Hradecka and Frantisek Cermak for a place in the semifinals.

In women’s doubles action, the top two seeded tandems advanced to the third round with ease. Wimbledon champions and world No. 1 Kveta Peschke and Katarina Srebotnik dominated sisters Alona and Kateryna Bondarenko 6-1, 6-2, breaking serve five times to advance in 58 minutes.

No. 2 seeds Gisela Dulko and Flavia Pennetta, who captured the Australian Open, also moved through in 58 minutes, dismissing Sofia Arvidsson and Vera Dushevina 6-4, 6-1. The Argentine-Italian duo won 74 percent of their service points and did not face a break point en route to victory.

On the men’s side, third seeds Michael Llodra-Nenad Zimonjoc and No. 4 seeds Mahesh Bhupathi-Leander Paes, the two hottest teams coming into the US Open, did not drop a set in their second-round victories.

Llodra-Zimonjic defeated Nicolas-Almagro-Maximo Gonzalez 6-3, 6-4, and Bhupathi-Paes, both former champions at the Open, cruised past Florian Mayer-Rogier Wassen 7-6(5), 6-2.

• Jack Sock Bio
• Bob Bryan Bio
• Melanie Oudin Bio
• Liezel Huber Bio
• Daniel Nestor Bio
• Steve Johnson Bio
• Katarina Srebotnik Bio
• Irina Falconi Bio