Williams sisters cruise into second round

BEIJING  - The Williams sisters cruised into the second round of the Olympic Games tennis singles on Monday, while Indian hope Sania Mirza was forced to retire hurt.

Number four seed Serena, the eight-time Grand Slam champion and a doubles gold medallist from Sydney in 2000 with sister Venus, but making her Olympic singles debut after missing Athens with a knee injury, beat Olga Govortsova of Belarus 6-3, 6-1.

The match was held over from Sunday at 2-1 in the second set when rain had forced all play to be cancelled.

Resuming on centre court on Monday, the American didn't hang around, breaking the Belarussian twice and holding serve to see out the second set 6-1.

Williams admitted that there had been butterflies before she took to the court with Govortsova.

"I was a little nervous going out there yesterday because, you know, it's the first time you played singles at the Olympics," she said.

"Obviously I wanted to win and I wanted to do well.