Zvonareva is ranked 21st in the world Photos from Roland Garros

It was an error-strewn performance from Williams but the Russian 22nd seed showed real determination to win 2-6 6-2 6-4 and ensure that for the first time in five Grand Slams, there will not be a Venus v Serena final.

Williams had struggled in the second round where she had needed three sets to see off the unseeded Australian Evie Dominikovic and said she was still suffering with a stomach injury that has plagued her in recent weeks.

If you go on to the court and don't think you can win you won't win - I believed in my chances Vera Zvonareva

However, the 22-year-old began well against Zvonareva, taking the first set comfortably.

But the Russian grew in confidence and began pulling her opponent from one side of the court to the other to take the second set and level the contest.

The 18-year-old continued to dictate the play at the start of the decider and she made the break in the second game as the under-pressure Williams was forced into making mistakes.

The American broke back and then had three chances to break again but squandered all of them, paying the penalty when she was broken again herself in the next game.

Capriati beaten

Zvonareva then held her nerve to serve out for a famous victory and a place in the quarter-finals where she will play compatriot Nadia Petrova, who also caused an upset, beating Jennifer Capriati.

Williams, who has contested and lost the last four Grand Slam finals, was philosophical in defeat.

HAVE YOUR SAY What a strangely passive performance from Venus From Ben, Coventry Join the debate

"I just need to go home and prepare. It's very disappointing but at this junction there is nothing I can do about it. I have to move on to the next tournament," she said.

"I just had a tough time keeping balls in. I don't really think I had the preparation I wanted. That made it hard too.

"Each match is tough if it's a loss, especially if it's a Grand Slam. They are all really disappointing.