SWIMMER Cameron van der Burgh set a new world record as he won South Africa’s first medal at the London Olympics in the men’s 100m breaststroke final last night.

Van der Burgh finished in a time of 58,46 seconds — 0,12 faster than the previous record held by Australian Brenton Rickard.

Another Australian, Christian Sprenger (58,93), finished second, and Brendan Hansen of the US (59,49) clinched the bronze medal.

Van der Burgh had qualified for the final in emphatic style on Saturday when he won his semifinal by breaking the previous South African, African and Olympic records with a time of 58,95.

"Tonight, as I came in, I said to myself, ‘a man can change his stars, you can write your own destiny tonight’. I had my chance and I took it," he said, after a victory that saw him lie back in the pool in sheer exhilaration at the finish.

Van der Burgh later said he was looking up at the sky — remembering Norwegian rival and world champion Alexander Dale Oen, who died earlier this year of a heart attack.

"I know that he was probably laughing down at me, thinking, ‘How can you go that time?"

Van der Burgh said: "I really don’t care about the world record. Once you become an Olympic champion you join the club, and they can’t take it away from you. One day I can tell my kids, when they are watching the Olympic Games, that I won that.

"One gold is better than Beijing already. If we can continue with this momentum, that would be good."

China surged clear at the top of the Olympic medals table yesterday, as two world records fell in the pool on a night when tough-talking James Magnussen aimed to lead Australia to relay swimming gold.

After dominating day one of competition with four gold medals, Chinese athletes hit paydirt once again with wins in shooting for Guo Wenjun before synchronised divers Wu Minxia and He Zi triumphed at the Aquatics Centre.

Guo successfully defended her 10m air pistol title with a thrilling last-shot finish at the Royal Artillery Barracks to overhaul France’s Celine Goberville, who had led going into the last round.

"I just focused on doing my best on the final shot," Guo said. "I think everyone is good, I just never give up."

Legendary diver Wu, meanwhile, clinched her third consecutive gold medal in the 3m springboard synchronised after wins in 2004 and 2008.

In the pool, American Dana Vollmer won the women’s 100m butterfly gold medal, clocking a world record of 55,98 for a crushing victory over China’s Lu Ying.

Vollmer became the first woman to break through the 56-second barrier as she added Olympic gold to the world title she claimed last year.

She bettered the previous world record of 56,06, set by Sweden’s Sarah Sjostrom in July 2009 at the World Championships in Rome.

"I just relied on my strengths," Vollmer said. "Just set it up well, passed a few people and charged it home."

France’s Camille Muffat won the women’s 400m freestyle gold with Britain’s defending champion Rebecca Adlington in third.

World champion Magnussen — tipped to be one of the stars of the Games — dived in at the last change to reel in US veteran Jason Lezak and lift Australia into last night’s relay final as top qualifiers.

It was Magnussen’s first swim at the Games and the "Missile" delivered on his brash confidence, clocking a sizzling 47,35 to surge past Lezak (48,04).

Defending Olympic champions America were second quickest ahead of Russia and France.

While China celebrated their burgeoning gold haul, hosts Great Britain were still waiting for their first win with cyclist Lizzie Armitstead having to settle for silver in a thrilling road race won by Marianne Vos of the Netherlands.

Over at Wimbledon, Maria Sharapova, Novak Djokovic and home hope Andy Murray were all winners on a rainy day.

Sapa-AFP and Reuters