Ariarne Titmus shattered fellow Australian Mollie O’Callaghan’s 200m freestyle world record on Wednesday, touching in 1min 52.23secs just weeks before defending her Olympic title in Paris.

She hit the wall at Australia’s Olympic trials ahead of O’Callaghan, who also went under her previous world record of 1:52.85, surging home in 1:52.48. Titmus was 0.81sec under the pace at 100m, holding on as her teammate pushed her to the limit.