Ryosuke Irie missed out on a medal Tuesday as he finished fourth in the men's 100-meter backstroke at the world swimming championships.

Irie touched the wall at the Danube Arena in 53.03 seconds, finishing 0.59 seconds behind gold medal winner Xu Jiayu of China. Americans Matt Grevers (52.48) and Ryan Murphy (52.59) took silver and bronze.

"I didn't think I'd do this well but it's not easy at the world's top level," said Irie, who decided to continue his competitive career after failing to win a medal at the Rio Olympics.

"The competition is getting tougher. (I feel) the gap in start technique and leg strength, and I need to work on my speed," he said.

Earlier, in the first race of the day, Yasuhiro Koseki rewrote a Japanese record with a time of 27.21 when he placed 10th in his preliminary heat in the men's 50-meter breaststroke.

He improved the record by clocking 27.17 in the semifinals, but finished 11th overall and failed to advance to the eight-man final.

"It didn't feel that way (speed wise) but I had the national record in mind as a criterion to qualify for the semis and I cleared that goal," Koseki said.

"But my time is way too slow compared to (Adam) Peaty," he said of the British swimmer, who set two world records in the same event — the first (26.10) in the heats, and the second (25.95) in the semifinals.