Ian Thorpe successfully defended his Australian 400 metres freestyle title at the Chandler Aquatic Centre in Brisbane today but missed out on breaking his own world record.
Thorpe was on his world record target after 300 meters but dropped off the pace in the final two laps to win in 3minutes 40.54seconds.
Thorpe set the world record of 3:40.17 at last year's world championships in Fukuoka, Japan.
The 19-year-old, who has set 16 world records in his career and won eight world titles, beat compatriot Grant Hackett by 4.85sec.
Hackett, the 1,500 metres world record holder, was second in 3:45.39 with Craig Stevens third in 3:50.79.
The Australian national championships also serve as selection trials for the Commonwealth Games and Pan Pacific championships. Thorpe could contest up to seven gold medals at the Commonwealth Games in Manchester in July.
"I would have liked to have swum faster and improve on what I'd done before, but it was still a pretty good time," Thorpe said.
Sydney Olympic Games bronze medallist Justin Norris won the men's 200m butterfly final in 1:57.30 from Heath Ramsay (1:57.53) and Grant McGregor (1:59.47).
Norris started slowly then took control of the race before having to hold off fast-finishing Ramsay.
Elka Graham retained her national women's 200m freestyle title with a victory in 1:59.77 over a strong field.
Butterfly specialist Petria Thomas, winner of three gold medals at last year's world championships, was second in 2:00.21 with world champion Giaan Rooney relegated to third in 2:00.80.
"I'm happy to have secured my Commonwealth Games spot so early in the meet even though I wasn't happy with the time," said Graham, who is ranked second in the world in the event.
Graham's time was almost three seconds outside the world record of 1:56.78 set by Germany's Franziska van Almsick eight years ago in Rome.
Jennifer Reilly won the women's 200 individual medley in 2:15.29 ahead of teenage prospects Jessica Abbott (2:16.96) and Alice Mills (2:18.38).
A 41-strong Australian team to contest the Commonwealth Games will be named after the six-day meet concludes on Saturday.
Australian won 23 of the 32 swimming gold medals awarded at the 1998 Commonwealth Games in Kuala Lumpur.
AFP