Qin, who swam the second leg, thus became the first swimmer to win three gold medals at the Fukuoka worlds.

"I feel so amazing," he said, adding that breaking the world record will be his next target.

But he acknowledged that he was very lucky to win the relay because he was very tired after the individual race.

"I was not in good form because of the 50m breaststroke final. Fortunately thanks to my teammates' excellent performance, we had the last laugh."

Zhang, the third leg, said, "This is our time, it's a great time. I have a beautiful and wonderful (team)."