The first day of the Yakult Singapore National Swimming Championships saw several meet records tumble.

National swimmer Quah Zheng Wen won the gold medal in the men's 100m backstroke with a time of 56.17 seconds, lowering the previous mark of 56.60 which he set last year.

It was also under the qualifying time of 57.27 for next year's SEA Games and meant that the 18-year-old Anglo-Chinese School (Independent) student is now eligible for selection for the June 5-16 event in Singapore.

Breaststroke specialist Christopher Cheong, 18, was next up as he won the men's 200m breaststroke at the OCBC Aquatic Centre.

The Temasek Junior College student stopped the clock in 2:18.51, erasing the previous best of 2:19.36 set by Lionel Khoo in 2012. It was also just a shade under the SEA Games qualifying time of 2:18.57.

The women's quartet of Quah Ting Wen, Amanda Lim, Celine Mark and Chan Zi Yi collected the third record of the night when they clocked 3:56.04 in the 4x100m freestyle relay to win the gold medal for Swimfast Aquatic Club (SAC).

The previous record was 3:57.48, set by SAC in 2012.