Stephanie Rice and Emily Seebohm both set world records on the opening night of the Australian Olympic trials in Sydney yesterday.
Rice demolished American Katie Hoff's 400 metres individual medley record while Seebohm broke Hayley McGregor's mark for 50m backstroke, an event not contested at the Olympics.
The 19-year-old Rice stopped the clock at four minutes 31.46 seconds, slashing 1.43 off the previous record of 4:32.89, set by Hoff at last year's World Championships in Melbourne.
Seebohm, 15, shaved 0.05 off the previous record of 28.00 set by American Hayley McGregory in Texas less than two weeks ago.