Quah Zheng Wen, Mylene Ong fail to qualify for semis

Quah Zheng Wen did not advance to the semi finals of the 200m backstroke (S'pore Sports Council)Quah Zheng Wen did not advance to the semi finals of the 200m backstroke (S'pore Sports Council)

Teenage swimmer Quah Zheng Wen failed to qualify for the semi-finals of the 200m backstroke event on Wednesday.

Swimming in Heat 1, the 15-year-old, who is the younger brother of national swimmer Ting Wen, clocked a time of 2:03.45 seconds

The fastest qualifier for this event is Tyler Clary of the United States with his time of 1:56.24s.

His fellow American and hot favourite Ryan Lochte is close behind with 1:56.36s, with Japan's pin-up Ryosuke Irie third in 1:56.81s.

The world record for this event, 1:51.92s, is set by American Aaron Peirsol in 2009.

Mylene Ong clocked 56.33s in the 100m freestyle, which is slower than her personal best of 55.70 (Getty)Mylene Ong clocked 56.33s in the 100m freestyle, which is slower than her personal best of 55.70 (Getty)

In the women's 100m freestyle event, Singapore's Mylene Ong clocked 56.33s to miss out on the semi-finals.

Swimming in Heat 3, Ong's time is also off her personal best of 55.70s.

China's Tang Yi led the way with a blistering time of 53.28.

Defending champion Britta Steffen of Germany, who holds the world record of 52.07s, only managed a time of 54.42s to scramble into the semis.