LONDON -- Alexander Vinokourov of Kazakhstan is leaving the Olympics in style.
He won the cycling road race Saturday by prevailing in a two-man sprint to the finish after favorite Mark Cavendish dropped from contention.
Vinokourov, who served a two-year ban after testing positive for blood doping during the 2007 Tour de France, has said he will retire from cycling after the London Games.
The women's 400-meter individual medley went to 16-year-old China's Ye Shiwen, who set a world record with a time of 4 minutes, 28.43 seconds. American Elizabeth Beisel took silver and China's Li Xuanxu grabbed the bronze.
China's Sun Yang flirted with a world record in the men's 400 freestyle (3:40.14).
South Korea's Park Tae-hwan was the silver medalist in 3:42.06, and American Peter Vanderkaay took the bronze in 3:44.69.
Australia finished the 400-free relay in 3:33.15, Netherlands won the silver, and the Americans got bronze.
Maybe it was first-game nerves or a hangover from the opening ceremony. But the U.S. had to overcome a sloppy performance to post an 81-56 victory over Croatia in its first game.
Next up for the Americans is Angola, which lost to Turkey 72-50 in its Olympic debut.
Wimbledon champions Roger Federer and Serena Williams each won their opening matches -- one struggled, one didn't.
Federer, a four-time Olympian, overcame a jittery patch and beat Alejandro Falla of Colombia 6-3, 5-7, 6-3.
U.S. First Lady Michelle Obama watched from the front row of Williams' box as the fourth-seeded American beat former No. 1 Jelena Jankovic of Serbia 6-3, 6-1.
Americans Kerri Walsh Jennings and Misty May-Treanor, who are trying for a third consecutive gold medal, beat Australians Tasmin Hinchley and five-time Olympian Natalie Cook in the final match 21-18, 21-19.
The No. 2 U.S. men's team of Sean Rosenthal and Jake Gibb needed just 33 minutes to put away South Africans Freedom Chiya and Grant Goldschmidt.
American Ariel Hsing, 16, is into the second round in Olympic table tennis. She defeated Yadira Silva of Mexico in four straight games on the opening day.
Destinee Hooker had 21 points and the United States held off late-charging South Korea 3-1 in their opening match.
The United States and Germany won heats in the blue-riband men's eight, leaving a host of top crews to vie for places in the final.
Only one crew progresses from each heat. The Germans, unbeaten in three years, finished a half length ahead of Britain at Dorney Lake. Olympic champion Canada came in last in a race fit for the final.
The U.S. beat Australia by a half length to reach Wednesday's final.
Elisa Di Francisca completed an Italian sweep in the Olympics' individual foil, winning the gold 12-11 in overtime against Arianna Errigo.
Errigo beat three-time defending champion Valentina Vezzali 15-12 in the semifinals, denying her Italian teammate a chance to become the first female athlete to win individual gold at four consecutive Olympics.
The 38-year-old Vezzali won a tense battle for bronze, 13-12 against Nam Hyun-Hee of South Korea.
Sarah Menezes of Brazil and Arsen Galstyan of Russia won the first two golds in the judo competition.
The second-ranked Menezes beat defending Olympic champion Alina Dumitru of Romania in the women's 48-kilogram final. Galstyan defeated one of the 60-kg favorites, Hiroaki Hiroaka of Japan, for his first Olympic medal.
South Korean marksman Jin Jong-oh won the 10-meter air pistol gold medal, improving on his silver in Beijing. Italian police officer Luca Tesconi won the silver, and Andrija Zlatic of Serbia took the bronze.
Top-ranked Yi Siling of China captured the first gold medal of the Olympics in the women's 10-meter air rifle at Royal Artillery Barracks. Sylwia Bogacka of Poland took the silver for her first major medal, and Yu Dan of China won the bronze.
Wang Mingjuan of China won the first gold medal of the weightlifting competition, taking the women's 48-kilogram title with a total weight of 205 kilograms.