Sullivan clocked a new time of 21.41 seconds and Libby took it home with 52.88 seconds.

Sullivan, competing in the semifinals of the Australian championships at the Sydney International Aquatic Centre on Thursday, broke the mark of 21.50 seconds set by France's Alain Bernard at the European championships last weekend in Eindhoven, Netherlands.

Bernard had broken Sullivan's mark of 21.56 set last month.

The previous record of 21.64, held by Russian Alexander Popov, was set in Moscow on June 16, 2000.

After missing out on Bernard's 100m record late on Wednesday, Sullivan said he hoped to improve his 50m time in Friday's final.

'I came in a bit more relaxed tonight, having got the 100m final out of the way last night and getting into the team for Beijing,' sullivan said moments after climbing out of the pool.

'It's sweet to get the record back off Alain after missing out on the 100m world record last night and after he broke the 50m record so quickly after I did it.'

'I know I have another swim left so there's always another chance. I hope I can go faster in the final, but I like to think I can take a couple of a hundredths of a second leading into a final, so we'll see.'

Trickett lowered German Britta Steffen's old mark of 53.30 by 0.42 secs. It is the second time Trickett has broken the 53-second barrier, but her previous time of 52.99 at the Duel in the Pool here last year was not ratified by governing body FINA because she was swimming against American superstar Michael Phelps.

'I can't tell you how much I wanted to break that record ever since doing it in the Duel in the Pool in April last year and I just wanted it so badly,' Trickett said.

'To see it officially up there on the scoreboard, it's just amazing. All my events are very important to me, but the 100m freestyle holds a special place in my heart and to know that four years ago I was going 0.8 seconds off, that is just awesome.'

'I've come so far, it's been an amazing journey, but I am just so happy to be part of this team,' she added.

'We have some fantastic girls coming through and it's going to be great for our relay team.' -- AP, AFP