Pakistan, July 27 -- Yu Zidi discovered swimming as a small child in order to cool off and now aged just 12 the Chinese sensation will showcase her prodigious talents at the world championships from Sunday.

The school girl with the cartoon dog themed swimming cap stunned the sport in May with a series of eye-popping times at China's national championships.

Yu, who turns 13 in October, clocked a blistering 2min 10.63sec in the women's 200m individual medley, the fastest time in history at that age.

She then romped to victory in the 400m medley in 4:35.53, which would have been enough for fourth place at the Paris Olympics last summer.

Yu also triumphed in the 200m butterfly in another scarcely believable swim that would again have only...