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Serena Williams has reached the second round of the women's singles in Beijing with a rain-affected 6-3 6-1 win over Olga Govortsova of Belarus.
The eight-time Grand Slam champion, seeded fourth for the event, is making her debut in the Olympic singles after missing Athens with a knee injury.
Williams had led the 47th-ranked Govortsova 2-1 in the second set on Sunday before rain forced all play to be cancelled.
However, resuming on centre court on Monday, the American broke her opponent twice before holding serve and taking the win.
Williams won gold with sister Venus in Sydney eight years ago but nevertheless admitted feeling tense before taking to the court.
"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. It's a great thing going out there playing for your country. It's cool.
"You get to play and see all these other athletes. You think about it, it's like, my God, it's the Olympics."
Playing her first match since winning Wimbledon for the fifth time, Venus later joined her sister in round two thanks to a 6-3 6-2 victory over Switzerland's Timea Bacsinszky.
Williams, who also won the singles gold in 2000, showed no sign of the knee injury that sidelined her in recent weeks.
In other matches, sixth seed Dinara Safina beat Italy's Mara Santangelo 6-3 7-6 (7-1), while another Russian, ninth seed Vera Zvonareva, beat Yan Zi of China 6-2 6-0.
Slovakia's Daniela Hantuchova, seeded 10th, saw off Japan's Ai Sugiyama 6-2 7-5, while number 15 seed Alize Cornet of France fought back from a set down overnight for a 4-6 6-1 6-4 win over the Czech Republic's Nicole Vaidisova.
Spain's Maria Jose Martinez Sanchez thrashed Australian Alicia Molik 6-1 6-1, while China's Peng Shuai outplayed Spaniard Carla Suarez Navarro 7-5 7-6 (7-2).
And India's Sania Mirza retired hurt after going 6-1 2-1 down in her first-round match against Iveta Benesova of the Czech Republic.