Jet-lagged Serena in Stanford semi-finals

Williams, the top seed and defending champion, won a 43-minute first set punctuated by five breaks of serve against her sixth-seeded South African opponent.

She said she was still feeling the effects of her triumph at Wimbledon last weekend and the subsequent flight to California.

Serena Williams returns to Chanelle Scheepers during the quarter-final of the WTA hardcourt tournament in Stanford on Friday. Pic/AFP

"I still have major jet-lag," said the 30-year-old US star, who said she awoke in the early hours of Friday and watched a DVD of popular series "Desperate Housewives".

"I've been up a long time," she said. "I'm tired now and ready to sleep, but it felt good to be out here - and especially good to win.

"I didn't want to take anything, so I was wide awake just like as if I was in Europe. I started the match slow and sluggish, but I expected that. I just stayed in there until I began moving better.

"I told myself just to get through it, win quickly. I'm a fighter, I just click - the mentality just kicks in."
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