China's Pan Zhanle enjoyed a "magic moment" after smashing his own world record on his way to victory in the men's 100m freestyle at the Paris Olympics on Wednesday.

It was China's first swimming gold of the Paris Games.

Pan powered to the finish in 46.40sec, beating the world record time of 46.80 he had set in February in Doha.

Australia's Kyle Chalmers, gold medal winner at the 2016 Rio Games, finished 1.08 seconds behind to take silver with Romanian David Popovici claiming bronze.

Pan's victory was a much-needed boost for China who have disappointed in the Paris pool so far.

"I was very surprised that I broke the record, it was a magical moment," said Pan, who only made the final by 0.06sec and failed to make it out of the 200m freestyle heats.

"China is improving step by step. Breaking this record is a small step in the right direction."

It was a bitter result for Chalmers who had to settle for silver in Tokyo and had hoped to regain his crown eight years after his triumph in Brazil.

"You look at Rio and I think I was so young and naive and didn't know what it meant to be an Olympian or to be an Olympic champion," he said.

"Eight years later, it means so much more to me to be able to stand on the podium and receive a silver medal."

Pan is the first Chinese swimmer to hold the world record in this event and now the first to win gold in what is the sport's blue riband event.

The bronze was the second medal in Paris for the 19-year-old Popovici who won gold in the 200m freestyle.