Olympic champion Kyle Chalmers fired a world championship warning with a sizzling swim in the blue riband 100m freestyle Wednesday, while Mitch Larkin smashed his own Commonwealth 200m medley record.
Chalmers, who won Rio Olympic gold ahead of Belgium's Pieter Timmers and American Nathan Adrian, touched in 47.35, less than half a second from Brazilian Cesar Cielo's 10-year-old world record of 46.91.
His time on night four of the six-day Australian trials was faster than he swam in Rio.
But Cameron McEvoy, the 2015 silver medallist who came fourth at the last world championships in Budapest, missed out, ending third in a top-class field that also boasted James Roberts, Alex Graham and Clyde Lewis.
Lewis came second, but outside the qualifying time needed to race the event in South Korea.
"I probably wasn't going as fast as I probably hoped, but it was a good solid race," said Chalmers.
"I definitely think I need to be out (first 50) faster to be competitive. A lot of guys are out in 23 (seconds) which I haven't done yet. It's something I'm working on."
Chalmers qualified for the 200m freestyle with a last-gasp victory on Monday over Lewis.
Larkin is also on fire five weeks out from the championships, shaving half a second off his own Commonwealth medley record, hitting the wall in 1:55.72.
"Really happy with that. I've been working really hard," said Larkin, who admitted he only swims the medley once or twice a week.
His main focus is backstroke, and he qualified for the 100m after clocking 52.38 this week -- his quickest time since 2015 when he won two world titles at Kazan and was named FINA male swimmer of the year.
He contests his pet event, the 200m backstroke, on Thursday.
In other races, Bri Throssell (2:07.39) qualified for the women's 200m butterfly while middle-distance queen Ariarne Titmus stormed through the 800m freestyle to win in 8:18.23 ahead of Kiah Melverton, who also touched inside qualifying pace.
Titmus, just 18, is shaping up as a serious threat to American great Katie Ledecky in South Korea. She smashed the Commonwealth record in qualifying for the 400m freestyle and also made the grade in the 200m.
Brisbane, Australia | AFP