Beijing - Samuel Wanjiru won the first Olympic marathon title for Kenya on Sunday as boxer Zou Shiming gave China a landmark 50th gold medal on the final day of the Beijing Games.

The United States dethroned men's Olympic volleyball champions Brazil, while Russia successfully defended its title in the group all-around team event in rhythmic gymnastics

Wanjiru shook off his last rivals in the closing stages and used the final lap in the Bird's Nest as a lap of honour before claiming victory in a fast time of 2 hours 6 minutes 32 seconds.

Two-time world champion Jaouad Gharib of Morocco took the silver in 2:07:15 hours and Tsegay Kebede of Ethiopia grabbed bronze in 2:10.00.

"This is history for Kenya. I am glad to have this one," said the 21-year-old Wanjiru, who finished second in the London Marathon earlier this year.

"I had to push the pace to tire the other runners and because my body gets tired when I slow down," said Wanjiru. "I tried to push with six kilometres left. It was hard but they couldn't keep up."

The winning time was fast given the quickly rising temperatures on a sunny day in the 42.195-kilometres race from Tiananmen Square past several Beijing landmarks to the stadium.

Marathon world record holder Haile Gebrselassie did not compete, saying he was worried about Beijing's pollution. The Ethiopian ran the 10,000m instead and finished sixth there.

The race took its toll as world champion Luke Kibet of Kenya retired after 30km and the 2004 Olympic gold medallist Stefano Baldini of Italy had to settle for 12th place in his last big race.

"The start was OK because it wasn't so hot but during the race the weather was bad. In the last 10km it was unbelievable what the Kenyans and Africans were able to do in these conditions," said Baldini.

In the boxing arena, Zou claimed the men's light flyweight gold medal when his Mongolian opponent Serdamba Purevdorj retired injured just nine seconds into the second round.

The victory for the 2007 world champion handed the host its first boxing medal of the Beijing Games and 50th gold overall during the 16-day competition.

In volleyball, the US men stunned defending champions Brazil to win their first gold medal in the event since 1988.

After dropping the first set 25-20, the Americans fought back to win the next three sets 25-22, 25-21 and 25-23 for a 3-1 victory. The bronze medal went to Russia, who beat Italy 3-0.

Russian won the group all-around gold in rhythmic gymnastics to successfully defend their title. The Russians amassed 35.550 points to edge China into second. Bronze went to Belarus.

The Games end later Sunday with a three-hour closing ceremony that organizers promised would be a "great, glittering party" for the record 11,249 athletes from 199 countries.

Hours before the ceremony International Olympic Committee president Jacques Rogge praised China for organizing an impressive Games in which US swimmer Michael Phelps and Jamaican sprinter Usain Bolt stood out.