PONTE VEDRA BEACH, FL, USA - The quarterfinal line-up is stacked with seeds at the MPS Group Championships, with one exception: Olga Govortsova will play Varvara Lepchenko in one of the matches.

In the second round, Govortsova breezed past Georgian qualifier Anna Tatishvili, 62 62, while Lepchenko, a lucky loser in the draw, blitzed Germany's Angelique Kerber, 61 61.

While Uzbek-born American Lepchenko, 24, will be contesting her first quarterfinal on the Sony Ericsson WTA Tour, it was Melanie Oudin, seeded eighth, who had to work hardest for her berth in the last eight, toiling for two-and-a-half hours to overcome China's Peng Shuai, 26 75 75.

Had Peng won an epic game on Oudin's serve at 5-5 in the second set - the American was down 0-40 - she would have served for the match.

But the 18-year-old held on, and ultimately it was her success at converting break points that made the difference. Oudin capitalized on all six of her opportunities, while Peng met with success on six of 14 chances.

"Every shot in the match mattered; every netcord, every ball hit on the line was going to determine the outcome," Oudin said.

"I fought my heart out there - I've lost a few close matches like this and I'm so glad I pulled this one out."

Oudin's reward is a quarterfinal clash with fourth seed Elena Vesnina, who beat Julia Goerges in straight sets, 63 62. Friday's schedule also sees No.3 seed Dominika Cibulkova take on sixth seed Aleksandra Wozniak.

In the evening session top seed and defending champion Caroline Wozniacki plays fifth seed Anastasia Pavlyuchenkova.

Check out photos from Ponte Vedra Beach right now in the gallery!

One of the doubles semifinals has also been set, with top seeds Bethanie Mattek-Sands and Yan Zi pitched against Andrea Hlavackova and Olga Savchuk. Peng and Chuang Chia-Jung, the No.2 seeds, are still in the hunt in the other half of the draw.