Wang touched in 1:55.00s ahead of Britain’s Duncan Scott (1:55.28s) and Switzerland’s Jeremy Desplanches (1:56.17s).

American Michael Andrew boasted this year’s fastest time coming into Tokyo but could only manage fifth while there was more disappointment for Japan’s defending world champion Daiya Seto, who came fourth.

Seto was one of the clear favourites to win the 400m individual medley earlier this week but failed even to make the final.

Wang was the top seed for the 200m after an impressive showing in the semifinal, and his pedigree goes further back after he won bronze both at Rio 2016 and at the 2017 world championships.

Scott pushed Wang close, finishing less than half-a-second behind the Chinese to smash the British record and collect his third medal in Japan, after taking silver in the 200m freestyle and gold in the 4x200m relay.

“It was always going to be tight and exciting,” said Scott.

“I know I’m going to come back strong. I’m really happy with the swim, it just wasn’t there. I’ve got to hold my head up high with that.”