Guo Jingjing, known as the diving diva of the Chinese team after she called one of her rivals, Blythe Hartley, "the fat Canadian", and her partner Wu Minxia gave China the first of what is expected to be eight gold medals off the boards at the Water Cube.

Guo and Wu, the current world champions, defended the 3 metre synchronised springboard title they won four years ago in Athens, finishing with 343.50 points. The pair led through all five rounds, their every twist and turn accompanied by wild cheering by their red flag-waving fans. The loudest cheer rang out when Guo and Wu received three 10s for synchronicity on their backward dive in the second round.

Julia Pakhalina and Anastasia Pozdnyakova, of Russia, took silver with 323.61, and the bronze went to Ditte Kotzian and Heike Fischer, of Germany, with 318.90. Pakhalina returned to the medals podium for her third Olympics, though this time with a different partner. The Russian won gold in the event at Sydney and silver in Athens with Vera Ilyna, who later retired. Fischer and Kotzian finished second to Guo and Wu at last year's World Championships.

Guo's off-the-board antics since the Games in Athens have been the subject of scrutiny by Chinese authorities. She has twice been threatened with removal from the national squad for "overt commercial activities". Guo made the Hong Kong gossip columns after a paparazzi shot of her dining with Kenneth Fok Kai-kong, the playboy grandson of the Hong Kong business tycoon Henry Fok, appeared in newspapers and magazines. She did not deny the relationship and has since engaged in modelling work and is the face of several cosmetic products in China.

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The judging of the competition came in for criticism at the Water Cube after Americans Kelci Bryant and Ariel Rittenhouse missed a medal by 4.5 points, finishing fourth with 314.40. US fans booed when the duo's marks for execution - ranging from 6.0 to 7.5 - were posted after their fourth dive, which dropped them to fifth place. That round kept them from a podium finish.

A team source said: "That was appalling. There were 10s given for things that clearly didn't merit that, and 6s given for mistakes that no one else saw."

The British pair, Tandi Gerrard and Hayley Sage, did well to make the last eight but stayed in that position throughout the final. In the third round, they dropped their reverse 2 ½ somersaults tuck and scored no higher than a seven.

Gerrard, 30, will dive on after the Games, but said: "I will be 34 by London 2012, so it's not for me. But that was my second Olympic final and its good to know that Hayley will be aiming for London and carrying our work forward."