By Clare Lovell
LONDON (Reuters) - Agnieszka Radwanska kept the bookmakers happy by justifying her seeding to beat Tsvetana Pironkova 4-6 6-3 6-3 on Monday and reach the Wimbledon quarter-finals.
The Polish fourth seed proved too strong for her 76th-ranked Bulgarian opponent and last year's runner-up is the highest ranked woman in the last eight.
But she made hard work of it.
Shortly after top seed Serena Williams tumbled out to Sabine Lisicki on Center Court, Radwanska conceded the first set to a fired-up Pironkova and everything pointed to another seed exiting early.
Radwanska, 24, looked listless and ill-at-ease on Court Two. Her serve lacked rhythm and she dropped it twice before getting a toe-hold in the set.
Admonishing herself for uncharacteristic errors, she saved four set points, two on her own serve, before succumbing to the Bulgarian's big forehand in a baseline rally.
But the former Wimbledon junior champion has an-all court-game that suits grass and she found her range in the second set, commanding the net and volleying with precision.
It was a low-key match in front of a subdued crowd which has become used to upsets after the first-week departures of Maria Sharapova, Victoria Azarenka and Sara Errani.
But Radwanska said she felt no great pressure as the highest seed standing
"It doesn't mean anything, especially here. So many weird scores," she said. "There's still a lot of players playing really great tennis. Every match is a different story. Doesn't matter what ranking they have."
Radwanska broke Pironkova's serve in the third game of the final set and, despite some resistance during attritional rallies, the 25-year-old Bulgarian had no way back.
Radwanska faces sixth seed Li Na in the quarter-finals after the Chinese disposed of Roberta Vinci.
"We've played a lot of times against each other, always good, long tight matches so I will have to play great tennis to beat her," Radwanska said.
(Editing by Ed Osmond)