Chad Le Clos won the 100m butterfly at the short course World Swimming Championships on Thursday. Photo: Aly Song/Reuters

SHANGHAI Chad le Clos raised both hands to the heavens after seeing off the new American golden boy Caeleb Dressel to win the 100m butterfly at the short course World Swimming Championships on Thursday.

In one of the most eagerly anticipated match-ups so far in the Chinese city of Hangzhou, the South African star romped to victory in 48.50sec.

That was 0.21sec ahead of rival Dressel, who at age 22 has drawn comparisons with US swim legend Michael Phelps.

It was a fourth 100m butterfly world title for Le Clos and some compensation for the disappointment that he suffered on Tuesday.

On the first day of competition the 26-year-old went under his own world-record time in the 200m butterfly but still came second to Japan's Daiya Seto.

Lisa Bratton grabbed a surprise gold in an American one-two in the women's 200m backstroke as the United States stepped up their dominance in the 25m pool.

Bratton pipped Olympic gold medallist Kathleen Baker into second by just 0.08sec in a thrilling finish with Australia's decorated Emily Seebohm taking bronze.  

Hungary's Katinka Hosszu, who won three golds at the Rio 2016 Olympics and is the short-course world record-holder, was stunned into fourth and out of the medals.

Bratton's nail-biting triumph in 2:00.71 took the United States' growing gold medal haul in these championships to eight.

They grabbed a ninth gold overall with victory in the mixed 4x50m medley relay.

In the men's 200m breaststroke, Russia's Kirill Prigoda blitzed his way to a world-record time of 2:00.16, beating home swimmer Qin Haiyang into silver by nearly one second.

Prigoda's rapid race was significantly quicker than the previous leading time of 2:00.44, set by Germany's Marco Koch two years ago.