LONDON: Serena Williams was left all alone trying to crush an unlikely uprising on Wimbledon’s hallowed lawns as sister Venus and Kim Clijsters suffered shock defeats in the women’s quarter-finals.

By the time defending champion Williams stepped on Centre Court before beating China’s Li Na 7-5 6-3, Venus had been thumped by Bulgaria’s Tsvetana Pironkova and Clijsters, seen as the main obstacle to another Saturday sister act, had crumbled to a three-set defeat against 21st seed Vera Zvonareva.

World number 82 Pironkova, who charmed the Court One crowd during a dazzling 6-2 6-3 defeat of Venus, will face 21st seed Zvonareva in the last four with the prize of a first appearance in a grand slam final tantalisingly close for both.

Serena, now overwhelming favourite to claim a fourth Wimbledon title and a 13th major crown, will direct her considerable firepower at Petra Kvitova in the other semi-final after the unseeded Czech saved five match points to beat Estonian qualifier Kaia Kanepi 4-6 7-6 8-6.

On a day of surprises it was Pironkova who stole the limelight as she inflicted a worst ever Wimbledon defeat on five-times winner Venus to become the first Bulgarian to reach a grand slam semi-final in modern times.

Afterwards the 22-year-old summed up exactly what it meant.

“Wimbledon has always been like a religion to me,” Pironkova, whose greater variety of shot completely nullified Venus’s power advantage. “I don’t think it’s just for me. I think it’s for all of the players.

“Because Wimbledon is the first tournament. It’s the oldest tournament. Growing up, every player is looking at Wimbledon. That’s like a dream.”

Venus, 30, won the singles here in 2007 and 2008 before relinquishing the trophy to Serena last year.