Beijing - Hosts China got a first swim gold at the Beijing Olympics on Thursday courtesy of Liu Zige's 100 metres butterfly success in a new world record time.

With Du Li winning the women's 50 metres rifle and Yang Wie triumphant in the men's individual gymnastics, China's gold tally went up to 20 - double the total of second-placed United States.

Alain Bernard gave France its first-ever gold in the showpiece 100m freestyle sprint and the Australian women's 4x200m relay team smashed the world record to take the gold.

Japan's Kosuke Kitajima repeated his breaststroke double from Athens 2004 and American star Michael Phelps, who had no final to swim the day after becoming the most successful Olympian with 11 golds, qualified for the 200m medley final.

Liu led a Chinese one-two to thrill the packed Beijing Water Cube in a world record time of 2 minutes 4.18 seconds.

Jiao Liuyang, whose time of 2:04.72 was also better than Jessicah Schipper's record of 2:05.40, won the silver medal. The Australian, Schipper, had to be content with bronze.

Liu, who won China's seventh gold swimming medal overall, said that she did not feel pressure going into the race.

"The night before the race my coach said to me that we will have two Chinese swimmers in the final, so you don't need to force yourself to win gold, you just need to try your best," she said.

In the men's 100m freestyle sprint, Bernard gained some revenge for earlier having lost the men's 100m freestyle world record to Eamon Sullivan as he beat the Australian to the gold medal in a time of 47.21. Sullivan finished second in 47.32.

American Jason Leazak and Brazilian Cesar Cielo Filho shared bronze in 47.67 while Dutchman Pieter van den Hoogenband failed in his bid for a third straight gold in the event by finishing fifth.

"This is the greatest day of my life. A dream has come true," said Bernard after the final of an event which saw three world records in the heats and semis. "I may have lost the world record but I am an Olympic champion and that lasts four years."

Kitajima, who won the 100m breaststroke on Monday, repeated his double from Athens as he won the men's 200m breaststroke event in the Olympic record 2:07.64 minutes. Australian Brenton Rickard won the silver and Frenchman Hugues Duboscq the bronze.

But the Aussies wrote the latest chapter in astonishing new relay world records.

Stephanie Rice, Bronte Barratt, Kylie Palmer and Linda Mackenzie clocked 7:44.31 minutes, slashing 5.78 seconds off the 7:50.09 a US relay swam last year at the worlds in Melbourne.

China was a popular silver medal winner in 7:45.93, while even the third-placed US team was under the old record time as they won bronze in 7:46.33.

It was the 18th world record set in the Beijing Water Cube at these games.

Phelps had the second fastest time in the 200m medley semi-finals behind Ryan Lochte ahead of Friday's final.

Away from the pool China won two other golds. Du Li overcame the disappointment of finishing fifth in the air rifle event on Saturday by winning gold in the women's 50 metres rifle three-positions competition.

And Yang Wie gave China its first all-around gold in artistic gymnastics since 1996 to secure his country's 20th gold of the 2009 Olympics.