American Serena Williams survived an uphill battle to join sister Venus in the Beijing 2008 Olympic Games tennis quarterfinals on Wednesday.

The fourth seed started sluggishly before putting together a hard-fought 3-6, 6-3, 6-4 win over talented French teenager Alize Cornet.

In contrast to her sister's struggle, Venus, the double gold medallist in singles and doubles at the Sydney 2000, scored a confident 6-3, 6-2 third round victory over No. 12 seed Victoria Azarenka from Belarus.

Serena, playing in her first Olympic singles event, racked up 48 unforced errors in the match and her serve was broken on three of five occasions.

By the middle of the first set, Serena was so disillusioned with her poor performance that she smashed a racquet in frustration.

"It was in the middle of the first set," Williams said about when she dismantled her racquet. "I missed so many shots and I was not playing anywhere near the way I was practising, so it was just kind of frustrating to have practised so well and to come out and do the total opposite."

Although Cornet challenged Williams until the end, exchanging brutally powerful baseline shots, the Frenchwoman eventually surrendered to her mightier opponent, an eight-time Grand Slam champion.

"Yeah, it's good to make quarterfinals, I'm excited. Anything is good at the Olympics and I'm still here."

Serena Williams will take a 4-1 winning record into the quarterfinal against No. 5 seed Elena Dementieva, but the Russian won their last meeting in the final of the 2007 Moscow tournament.

(Xinhua News Agency August 13, 2008)