China's Pan Zhanle obliterated his own 100m freestyle world record at the Paris Olympics on Wednesday as he took an astonishing gold medal in the event and humbled a slew of champion rivals.

The 19-year-old's time of 46.40 seconds shaved an incredible 0.40 seconds off his previous mark set at the world championships in Doha in February, when he announced himself to the world with a stunning relay leadoff swim.

Australia's silver medalist, Kyle Chalmers, finished a yawning 1.08 seconds behind the incredible Pan, while David Popovici finished a further .01 seconds behind to take the bronze for Romania.

There was no easing in for Pan, who took off like a rocket and mowed down the opening 50 meters in an outrageous 22.28 seconds.

The Chinese sensation blew any hopes Chalmers and Popovici might have had of catching him out of the water, as he stretched his lead and flew to the wall to earn his first Olympic gold medal five months after winning the world title.

Chalmers, the gold medalist at Rio 2016, took his second silver in the event, having finished second behind Caeleb Dressel at the Tokyo Games.

Popovici, who previously held the world record before Pan took it at Doha, added the bronze to his 200m freestyle gold medal at Paris.