WARSAW, Poland - Elena Dementieva's lead-up to the French took another wrong turn, as she lost her opening match at the Polsat Warsaw Open. Caroline Wozniacki almost followed her to the sidelines but made it through.

Watch live matches from Warsaw starting Thursday on TennisTV!

Dementieva, the No.2 seed at the Premier-level tournament, split sets with Tsvetana Pironkova and twice led by a break in the third but wasn't able to close out the hard-hitting Bulgarian qualifier, losing in just a few minutes shy of three hours, 75 46 64. It was her third loss in five matches since the start of the European clay season, falling early at Rome and Madrid in the last two weeks.

Pironkova, ranked No.100 in the world but once as high as No.40, picked up her fourth career Top 10 win, having previously beaten the likes of Venus Williams, Ana Ivanovic and, most recently just last fall, Vera Zvonareva.

In a near-upset, No.1 seed Wozniacki was nearly ousted by Polona Hercog, falling behind 3-0 in the third set to the talented young Slovenian player. But the No.3-ranked player in the world showed her mettle, grinding out six of the last seven games - including digging out of a 0-40 hole while serving for the match at 5-4 - to prevail in the two-hour, 11-minute first-time encounter.

"My opponent started out very strongly, but I kept fighting," Wozniacki said. "I think my biggest weapon today was my fighting skills. It was tough and it looked like I wouldn't be able to get it back, but I'm glad I pulled it off."

Chinese 1-2 Li Na and Zheng Jie had no problems whatsoever, with No.3 seed Li rolling past Polish wildcard Katarzyna Piter in 51 minutes, 60 63, and No.5 seed Zheng losing even fewer games to beat Italy's Tathiana Garbin, 61 61.

Others snapping up quarterfinal berths were No.6 seed Alona Bondarenko, Alexandra Dulgheru, Sara Errani and qualifier Greta Arn. Bondarenko and Dulgheru were the finalists here last year, with Dulgheru winning her first Sony Ericsson WTA Tour title with a three set win over Bondarenko.