Kylie Palmer produced the swim of the second night of Olympic trials, beating Bronte Barratt in the 400m freestyle and stealing her Australian record in an impressive 4:03.40.

Barratt was second in 4:05.74, ensuring their rivalry will continue in London.

"I've trained pretty hard but you can never be sure of what you're going to do," Palmer said.

"I didn't want it to be as close this year as it was last year so, I'm really happy I could pull away from Bronte in that last 100m.

"I'm really happy with it."

Christian Sprenger broke the elusive one-minute barrier in winning the 100m breaststroke title.

Sprenger produced his best performance in a textile suit, clocking 59.91 seconds to turn the tables on fierce rival Brenton Rickard, who was second in 1:00.13.

It ended Rickard's eight-year grip on the event, though the pair tied for the title in 2009.

"The 60-second barrier was something a big part of me wanted to break," an emotional Sprenger said.

Libby Trickett just missed her first chance at London Olympic qualification as golden girl Alicia Coutts booked her ticket with a hard-fought win in the 100m butterfly final.

Coutts defended her national title in 57.59 seconds to fend off a fast-finishing Jess Schipper (57.88), who also booked an Olympic berth.

Trickett, meanwhile fell one placing short in her first attempt to book a spot on the team for London, finishing third in 58.64.

The 27-year-old will now turn her attention to the 100m freestyle, starting on Monday.

After an impressive swim in the morning heats, Ian Thorpe faded late in his semi-final, clocking a slower time of one minute 49.91 seconds to manage only the 12th fastest time.

The 200m was considered Thorpe's best chance at qualification and his hopes now ride on finishing top six in a strong field for the 100m freestyle, starting on Sunday.

Thorpe was clearly shattered.

"I'm terribly disappointed with that," Thorpe said on pool deck.

"I thought I could and thought I would swim a lot quicker, much quicker.

"I'm not sure why ... this was slower than my time this morning.

"... The fairytale has descended into a nightmare."

Ryan Napoleon (1:47.51) was fastest qualifier into the final ahead of Thomas Fraser-Holmes (1:47.57).

Thorpe, who announced his comeback in February last year after five years out of the sport, had raised hopes he could claim a place on the team with an encouraging heat swim on Friday. It was not to be.

"I haven't had to deal with this kind of disappointment," Thorpe said at the post-race press conference.

"I've never felt this utterly gutted and speechless after a race.

"It's tough, but this is sport. This is what we do as athletes."

But with the 100m freestyle remaining- and a juicy six positions on offer- there is still a glimmer of hope of Thorpe getting on the 2012 Olympic Team.

"I'll try not to let this detract from that possibility.

"I still want my spot on this Team.

"Tomorrow as best I can I'll try to let go of what happened and try and get ready for the 100m," he said.

An emotional Thorpe was encouraged by his teammates ahead of the 100m freestyle heats on Sunday.

"It's been great around pool deck... People are finding the positives for me when I couldn't see any of them."

In other semi-final action, Leiston Pickett was the fastest qualifier into Saturday's 100m breaststroke final, clocking 1:07.41 to beat Olympic champion Leisel Jones (1:08.44).

Hayden Stoeckel qualified fastest for the 100m men's backstroke decider while Belinda Hocking led the way into the women's final, clocking 59.39 seconds to qualify ahead of Emily Seebohm (1:00.06).

Seebohm earlier won the non-Olympic 50m backstroke while Chris Wright won the men's 50m butterfly.

AOC with AAP