KAZAN, RUSSIA - Singapore swimmer Quah Zheng Wen clocked 54.40seconds in the men's 100m backstroke at the Fina World Championships on Monday afternoon, re-writing his own national mark.

His timing is an improvement over the 54.51sec he set at the SEA Games in June. He finished 21st out of 67 swimmers overall, and did not advance to the semi-finals. Quah, who turns 19 next month, had to finish among the top 16 to earn a place in the semi-finals.

In the men's 200m freestyle event, Danny Yeo clocked 1:51.29 to finish 49th overall out of 79 swimmers. He did not advance to the semi-finals.

Rachel Tseng, swimming in the women's 1,500m freestyle preliminaries, clocked 17:26.53 to finish 23rd overall out of 25 swimmers. She did not advance to the final.

Joseph Schooling will be in action at around 11.15pm, swimming for a place on the podium in the 50m butterfly final.