Portugal Colonial - Titmus goes close to 200m free world record as McKeown fires

Young prospect Mollie O'Callaghan, 18, was also on fire and has qualified for four events at the world championships in Budapest next month -- the 50m and 100m backstroke and 100m and 200m freestyle.

Titmus dethroned American great Katie Ledecky to win the Tokyo Olympic 200m and 400m gold last year and was under world record pace until the final few metres in Adelaide.

She hit the wall in 1:53.31, just off Federica Pellegrini's super-suited world record of 1:52.98 set in 2009 and quicker than her swim to win the title in Japan.

It was fastest time, by far, in the world this year.

Despite her form, Titmus has opted out of Budapest and will only compete at the Commonwealth Games in Birmingham in July.

"Sometimes people think that when you become Olympic champion you can become complacent but more than anything I think it has inspired me more," she said poolside.

"I'm swimming pretty well so happy with that, but will still not be going to the worlds and concentrate on the Comm Games."

Ledecky punched her ticket to Hungary with a dominant win at the US trials last month, but her 1:55.15 was nearly two seconds slower than Titmus.

The pair are scheduled to face-off at the "Duel in the Pool" -- pitting Australia against the United States -- in Sydney in August.

O'Callaghan was second to Titmus in 1:54.94 and will carry the challenge to Ledecky at the worlds.

The fast-rising O'Callaghan had already won the 50m backstroke and 100m freestyle titles, and booked a fourth ticket to Budapest by coming second to McKeown in the 100m backstroke.

McKeown set the current world mark of 57.45 in the same Adelaide pool during the Olympic trials in June last year, carrying the form into Tokyo to claim the backstroke double.

She was unable to go better on Friday, touching in 58.49, below her best after backing up from a gruelling 400m medley win on Thursday.

"It was a rough double up to come back today and blow out the cobwebs again. But I'm happy with that time, it's pretty decent," she said. "I'm looking forward to going a bit faster."

Olympic 200m breaststroke champion Zac Stubblety-Cook followed up his stunning new world record on Thursday, when he clocked 2:05.95 to become the first man under 2:06, by clinching the 100m.

The 23-year-old hit the wall in 59.60 to ensure he will swim both events in Hungary.

With British world record holder and Olympic champion Adam Peaty ruled out with a foot injury, the door is open for Stubblety-Cook to claim the double.

Jenna Strauch added the 200m title (2:23.26) to the 100m she had already claimed, while Tokyo Olympic bronze medallist Brendon Smith (1:58.59) took out the men's 200m medley.

R.J.Fidalgo--PC