A training partnership with the world's fastest 100-meter freestyle swimmer has enhanced Libby Trickett's status as the world's fastest woman in the event.

Trickett swam the second fastest women's 100 freestyle time ever Thursday night, missing her own world record by 0.11 when she touched in 52.99 seconds to win at the Australian trials and secure a place at the world championships in Rome this July.

Trickett, the reigning world champion in the event, started training with men's world record holder Eamon Sullivan in Grant Stoelwinder's squad after the Beijing Olympics, where she settled for silver in her favored 100 freestyle but won two other gold medals.

She is the only woman in the elite squad and credits the extra competition for improving her freestyle stroke.

"Because I am such a competitive person I don't feel like I want to race the other girls anymore," she said after the race. "I am sort of tired of it. I just want to be able to do my best and race my best. That is enough competition for me."

Sullivan qualified for Friday's men's 100 freestyle final by winning his semifinal in 48.24 seconds, just two months after undergoing hip surgery.

In other events, Sydney and Athens Olympian Geoff Huegill missed out on qualifying for the world championships by finishing fifth in the 50 butterfly in his comeback to top competition.

Ashley Delaney won the 200 backstroke in 1 minute, 55.82 seconds to beat teammate Hayden Stoeckel's Commonwealth record.

Emily Seebohm won the women's 100 backstroke while Christian Sprenger (1:00.64) and Brenton Rickard deadheated in the men's 100 breaststroke.

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