MELBOURNE: Tokyo gold medallist Emma McKeon and former world champion Mollie O'Callaghan reached the women's 100m freestyle final at Australia's Olympic trials on Friday but seasoned sprinter Cate Campbell missed out by the narrowest of margins.
Meg Harris was fastest in the heats with a time of 52.52 seconds at Brisbane Aquatic Centre, 0.05 better than O'Callaghan.
McKeon, who won the 50m and 100m gold medals at the Tokyo Games, was sixth quickest but four-times Olympian Campbell missed the top eight by a hundredth of a second.
The eighth spot in the final was taken by 17-year-old Milla Jansen, leaving the 50m freestyle as Campbell's last chance saloon for Paris.
Campbell's younger sister Bronte, a double Olympic relay champion, was fourth quickest behind third seed Shayna Jack, with Olivia Wunsch a surprise finalist as the fifth seed and the experienced Brianna Throssell seventh.
The evening session's final promises to be a thriller as the swimmers battle for the two individual berths and a place on the relay team which won the 4x100m freestyle gold at Tokyo.
The top six will have priority selection for the relay, and making the Australian team is usually a ticket to an Olympic medal.
Olympic champion Zac Stubblety-Cook took top seeding in the men's 200m breaststroke final after winning his heat in 2:08.40, a couple of seconds clear of the second fastest, Joshua Yong.
Jenna Strauch topped qualifying in the women's 200m breaststroke in 2:24.83 but will need to shave that down a bit in the final to meet Australia's Olympic qualifying standard (2:23.91).
Bradley Woodward, part of Australia's silver medal-winning mixed medley teams at the last two World Championships, was fastest in the men's 200m backstroke heats.