Reigning 100 free champ Emma McKeon doesn't qualify for Paris ...

MELBOURNE, Australia -- Mollie O'Callaghan swept to victory in a stacked 100-meter freestyle final, while Emma McKeon's hopes of defending her gold medal in Paris were crushed at Australia's Olympic trials on Friday.

O'Callaghan won in 52.33 seconds, 0.39 clear of runner-up Shayna Jack, who wept after securing the second individual 100-meter berth three years after missing Tokyo while banned for doping.

McKeon claimed the 50 and 100 freestyle golds in a record haul of seven medals at Tokyo but finished sixth in Friday's final and can be selected only for the relays.

O'Callaghan has had a roller-coaster week, swimming superbly while having her 200 freestyle world record swiped in the final by Ariarne Titmus.

The 20-year-old was disappointed with her 100 swim at the Brisbane Aquatic Centre but glad to top a quality field.

"At the end of the day, trials is just to make it on the team, so I'm pretty stoked with that," O'Callaghan said poolside. "But you know there's that little extra that you want."

A fixture in Australia's 100-meter freestyle relay teams since the 2008 Beijing Olympics, Cate Campbell was devastated after failing to qualify for the final. She has an uphill battle to win a 50-meter freestyle berth and secure a fifth Games appearance.

Her younger sister Bronte, however, finished fourth in the 100-meter final to nab a spot on the relay team along with Meg Harris (third) and 18-year-old Olivia Wunsch (fifth).

Bronte Campbell struggled to hold back tears as she paid tribute to 32-year-old Cate, who won two relay golds at Tokyo and the individual 100-meter bronze.

"I felt devastated for my sister this morning," she said. "But she is absolutely incredible. I mean, she held this individual spot in the 100 freestyle for 11 years. I think that's got to be a record in Australia."

Olympic champion Zac Stubblety-Cook earlier qualified for the men's 200-meter breaststroke with a time of 2:07.40 and will be joined in Paris by runner-up Joshua Yong.

Ella Ramsay will swim in the women's 200-meter breaststroke after winning the final in 2:22.87, 24 years after her father Heath swam butterfly for Australia at the 2000 Sydney Games. The favorite Jenna Strauch was second and missed Australia's Olympic qualifying standard but could still swim the event in Paris if selectors use their discretion.

Bradley Woodward, part of Australia's silver-medal-winning mixed medley teams at the past two world championships, booked his first Games by winning the 200-meter backstroke in 1:56.22.

Sam Short skipped the 1,500 meters after struggling with a stomach bug in the lead-up to the trials, leaving Matthew Galea to win the final in 14:58.96. However, Galea's time was short of Australia's qualifying standard (14:54.29), opening the door for selectors to pick Short in the event.

Short, who took the 1,500 bronze at last year's world championships in Fukuoka, Japan, already has a qualifying time in the event and secured one of the 400-meter berths for Paris this week.