ADELAIDE • Former world champion Cate Campbell edged out her sister and reigning world champion Bronte to win an epic 100m freestyle final at the Australian Championships and Olympic trials yesterday.

Cate, who won the world crown in 2013, swam close to her personal best time in 52.38sec to edge out Bronte by just 0.20sec. They will now head to the Rio Olympics to resume their friendly rivalry in the event.

Testament to the quality of the race was that Cate's time was 0.14 under the time Bronte took to win the gold medal at last year's world championships. They showed the punishing effects of the gruelling race, wincing and gasping in pain during the poolside interview. Both are coming back from injuries.

Cate had shoulder surgery in late 2014 and carried a strained wrist into these championships. Bronte has been troubled by hip and shoulder problems this year.

Bronte said: "There's never been a tougher 100m freestyle final at this national championships and it took me pretty much my best time just to make the team."

Only the top two claimed the individual places in the event. Australia, however, is also gearing up for a potential gold medal-winning women's relay team, with Emma McKeon clocking 52.80sec for third, while Brittany Elmslie clocked 53.54sec in fourth.

"It's exciting. There are four women who were swimming under 53 seconds," Cate said.

Double Olympic relay champion Melanie Wright, 29, retired yesterday after failing to make the team for Rio. She won gold in the 4x200m free at Beijing 2008 and the 4x100m free in London four years ago.

She was 13th fastest in the 100m freestyle semi-finals and failed to advance to the final.

AGENCE FRANCE-PRESSE, REUTERS