It's China's Olympics as US all set to finish second

Beijing: Heavy rain lashed Beijing on Thursday as Jamaica prepared to complete its dominance of the glamour sprints in the women's 200 meters final.

The United States was on the verge of handing over its mantle of Olympic supremacy to China but its downfall has been across the board and not just at the hands of the emerging Chinese.

Jamaica laid claim to the once-US sprinting stronghold, as Usain Bolt became the first man to smash world records in winning the 100m and 200m double at one Games.

Veronica Campbell-Brown will lead the Jamaican women in Thursday's 200m final aiming to complete the Caribbean sweep after shutting out the Americans for all three medals in the 100m

As a deluge broke over Beijing, and temperatures fell to around 24 degrees Celsius (75 Fahrenheit), athletics field events were delayed until the rain eased late morning and the BMX semi-finals were postponed until Friday.

In Hong Kong where the equestrian is being held, looming Typhoon Nuri was beginning to be felt, threatening the individual showjumping final.

The Equestrian Company, which is running the event, said it was monitoring the situation "very closely" but expected the competition would go ahead.

At the Bird's Nest in Beijing, track events continued where reigning champion Jeremy Wariner is odds-on favourite to salvage some US honour in the men's 400m. His greatest threat is set to come from compatriot Lashawn Merritt.

The 1.3 billion Chinese, meanwhile, will have to watch Dayron Robles star in the 110m hurdles final which was supposed to showcase their national hero Liu Xiang who pulled out injured in the heats.

China continued to control the medals table with 45 gold to 27 for the United States and 16 for Great Britain.

The outstanding US pair Kerri Walsh and Misty May-Treanor added to the US cause in the women's beach volleyball final, beating China's Tian Jia and Wang Jie 21-18, 21-18 to register their 108th consecutive victory.

China took silver and bronze for their first Olympic medals in the sport to continue their ever-expanding sporting prowess.

Other ground-breaking performances include first golds in yachting, archery and fencing while their women's hockey team will make their maiden final on Friday.

Brazil, armed with two of the most explosive talents in women's football, face their Olympic nemesis United States in the women's football final.

With Marta and Cristiane the two goal-scoring sensations of the tournament so far it will be difficult for the United States to retain the title they have won in two of the past three Olympics.

In early events completed Thursday, world champion Olga Kaniskina of Russia led from gun to tape to win the women's 20 kilometeres walk in atrocious conditions, with Norway's Kjersti Platzer second.

Maarten van der Weijden of the Netherlands won the inaugural men's 10 kilometets open water marathon swim from Great Britain's David Davies.

Following the postponement of the two BMX cycling finals, there were 21 gold medals on offer Thursday, with finals also in diving, modern pentathlon, sailing, softball, taekwondo, water polo and wrestling.