American second seed Serena Williams spurned eight match points en route to a hard-fought 6-3, 6-7 (5/7), 6-4 victory over Czech Klara Zakopalova in the French Open first round in Paris on Tuesday.

It was Williams's first clay court win of the season after an injury-troubled start to 2009 and avenged her surprise defeat to Zakopalova in the first round of the WTA Marbella event in April.

But what looked like a routine win when Williams, the 2002 champion, was poised on the threshold of round two at 5-4 up in the second set turned into a far more arduous encounter against an increasingly obdurate adversary.

"I think I played a very good match and I think Serena will be playing better and better, so it was my best chance to beat her," said a glum Zakopalova, whose battling display thrilled the fans on Court Suzanne Lenglen.

"The public were fantastic. I'd never played in front of a crowd like this in my life. I'd like to thank the people here in Paris because it was unbelievable."

Williams, who is bidding for an 11th career Grand Slam and third in succession after the US Open and the Australian Open, started well, wrapping up the first set in just over half an hour.

Zakopalova, the world number 100, then took the fight to her illustrious opponent in the second set, taking advantage of some erratic groundstrokes from the American to open up a 3-0 lead.

Williams, who played with a black bandage above her troublesome left knee, dug deep to break back, level and forge ahead with some trademark big hitting, but after seeing five match points come and go she allowed Zakopalova back into the match.

The world number two was clearly irritated by her failure to convert her chances and she paid the price when Zakopalova produced some stunning winners before prevailing in a dramatic second-set tie-break.

Zakopalova broke again to take a 2-1 lead in the decider, but Williams stopped the rot with a double-break to lead 5-2, only to spurn three more match points on her opponent's serve.

The Czech produced a nerveless backhand winner down the line to break in the next game, before Williams finally put the match beyond her at the ninth attempt when Zakopalova swatted a forehand into the tramlines.

Williams will now meet Virginia Ruano Pascual of Spain for a place in the third round.