He did not slow down, or stretch his arms or slap his chest, this time. But he still won the 200m sprint in world record time, giving himself the best present on the eve of his 22nd birthday.

Maybe he did not want to take a chance until he crossed the 200m finish line yesterday. After all, it was the great Michael Johnson whose world record he was after, unlike the 100m in which he broke his own on Saturday.

The at-capacity 90,000-person crowd at the Bird's Nest knew about his birthday and sang Happy Birthday to Bolt as he ran a lap of honor.

So what do the spoils add up to after the end of the historic dash? Usain Bolt has become the first athlete to set world records in the 100m and 200m sprints at the Olympics. He is the first man to win the golden double after Carl Lewis in the 1984 Los Angeles Games. The great Jesse Owens has done that too, but even he couldn't break both the records.

Johnson had been prophetic when he said after the 100m dash that Bolt might one day shatter his world 200m record of 19.32 seconds, set in Atlanta 1996. It took the Jamaican just four days to make that prophecy come true.

"Nothing he does will shock me," Johnson had said. "He has been working on his start and the first part of the 100m proved he has worked on that. He's going to have to turn the corner a lot better (in 200m) and run the corner better." It was the most impressive athletics performance "I've ever seen in my life," Johnson had said about Bolt's 100m run.

Johnson, now a commentator for the BBC, pretended to be gutted as Bolt completed the 200m in 19.30 seconds yesterday. No words. But then he had made his feelings known on Saturday itself.

It was a day of another stunning performance. Though Natalie du Toit finished only 16th of 20 in the maiden women's 10km swimming marathon, she won the hearts of spectators and competitors alike. The South African swimmer's left leg is amputated from below the knee.

Elsewhere, Yin Jian sprung a surprise in sailing, winning China's first gold in the sport. Yin hailed it as the ultimate reward for years of battling injuries and spending long periods training away from home.

"When the (Chinese) flag was being raised I was thinking about the hardship I have gone through for this gold medal," she said.

On a day, when only 11 golds were to be won, China took two - the other in women's taekwondo, taking its gold haul to 45. World champion Wu Jingyu won the women's under 49-kg class on the first day of the Games taekwondo competition.

This is the first time China has won this class since the taekwondo entered the Games in Sydney in 2000.

Mexico's Guillermo Perez won the men's under 58-kg gold beating Dominica's Yulis Gabriel Mercedes. Afghanistan's Rohullah Nikpai won one of the two bronzes for men - and his country's first ever Olympic medal .

In women's hockey, China beat defending champion Germany 3-2 to move into the final, where it faces the Netherlands.