Usain Bolt celebrates a gold medal and world record in the 200 metres yesterday in the Games of the XXIX Olympiad in Beijing, China - ap

beijing, china (cmc)

Fatigued after running seven races in four days prior to the men's 200 metres final, Jamaican Usain Bolt said he decided to give the big race one last blitz yesterday.

The effort not only yielded the 200 metres title and the Olympic sprint double for the 22-year-old, but saw him smash American Michael Johnson's 12-year-old record of 19.32 seconds, posting a new mark of 19.30 seconds.

"Well, I wasn't really expecting it (record), but I told myself I was going to come out here and I'm going to leave everything on the track and I did just that. yesterday I was a little bit tired, but I decided that last night [I would give it everything]," Bolt said.

Did what I had to do

"I told my roommate Maurice Smith who is coming up, I told him that I'm going to come out here and leave everything on the track and he said 'go do what you have to do'. so I came out here and did what I had to do," he added.

Bolt had a superb start, leaping from the blocks and bursting through the curve to establish himself as the clear favourite heading into the stretch.

Aware the field had been reduced to simply admirers for most of the final stretch, Bolt raced against the clock to set his second world record of the Games.

"I looked and I was like, I can do this, so I just started leaning. I just wanted it real bad. It means a lot to me, so I'm happy with myself," said Bolt.

The performance follows on from his fabulous run in the 100 metres at the weekend, where he set a new world and Olympic record in capturing that title in 9.69 seconds.

Birthday present

Wednesday's victory also meant that he became the first runner in 24 years to achieve the Olympic sprint double. The feat was the perfect birthday present for Bolt who turned 22 yesterday, but he said his mind might be on getting much needed rest, not birthday celebrations.

"I don't even know [about celebrations]. Right now I'm just thinking about getting some rest. I'm so tired, my body is tired. I'm just trying to get some rest, now pretty much," Bolt said.