China's Gong Jinjie and coach Benoit Vetu, before Saturday's first round of keirin.?[Photo/IC]

When China's Gong Jinjie and Zhong Tianshi won the women's team sprint to secure their country's first track cycling gold it was hard to see their faces under bright red helmets.

But the beaming smile across their French coach's face was clear for all to see.

"It's the best feeling in my sporting life," said Benoit Vetu, who has coached the Chinese sprint team since 2013.

The Chinese broke the world record in qualifying and were too strong for Russians Anastasia Voinova and Daria Shmeleva in the final on the new Rio track.

The gold comes after bitter disappointment at the world championships in March, when Jinjie and Tianshi were disqualified from the final for changing a fraction too early.

Vetu was so distressed by the result that he broke his wrist smashing a table in anger.

"It's a bit painful still, but it's a good reminder now," he said.

"I work with passion. This is not just my job, this is my passion."

Asked whether he would continue to coach the Chinese team, Vetu said he needed time to think about his next step.

"I will go back to France, have a rest and decide after that," he said.