Britain's Christine Ohuruogu captures the gold medal of the women's 400 meters in 49.62 seconds at the Beijing Olympic Games on Tuesday. [Xinhua]

Britain's Christine Ohuruogu captured the gold medal of the women's 400 meters in 49.62 seconds at the Beijing Olympic Games on Tuesday.

The reigning world champion ran aggressively from the start and began to take a lead after 100 meters. With 200 meters to go, she managed to widen the gap with Sanya Richards of the United States, who was in hot pursuit. She finally drew away from her rivals in the last a few seconds to secure her victory.

Jamaica's Shericka Williams finally overtook Richards to claim the silver in 49.69 seconds, beating the runner-up to the 2005 World Championship, to the third place in 49.93 seconds.

The 2008 best performer Amantle Montsho of Botswana was unexpectedly thrown to the last place among 8 finalists with a lackluster 51.18 seconds, in sharp contrast with her 49.83 seconds on April 30.

"I am just so proud of myself," the new champion exclaimed after the race. "I know I can perform well when I need to. I may not have a good season but, like at the world championships, that's what I train all year for.

"You always have all these dreams about winning, but you never think your dreams will be reality. I just ran across the line, thinking, 'I won!'," she said.

Claiming four golds of Golden League and Grand Prix in 2008, the 24-year-old was not in her top form, compared with her remarkable 49.61 seconds in the 2007 Osaka Championships.

"I didn't sleep very well the last couple of nights. I'm so tired," she said. I'm just happy it's over, so I can go to sleep."

For Williams, a silver was more than satisfied. "I tried my best. A season's best and a personal best, and this is my best. I couldn't ask for more," she said.

"After what happened to Asafa, I thought, damn, we have to motivate ourselves and do it for him," the national champion in Jamaica took her fellow Asafa Powell's failed attempts in men's 100 meters as a motivation to run today.

Asked about why she missed out the gold, she said: "I was thinking too much about passing Richards, and didn't give Ohuruogu too much focus."