Breaking a world record with Michael Phelps in the pool should be every swimmer's dream.

It is not even the highlight of Libby Lenton's week.

The speed machine used the rare occasion of competing against the American superstar in the lead-off leg of a mixed 4x100m relay to crush the 100m freestyle world record at the Duel in the Pool in Sydney.

She hit the wall at 52.99 seconds to crush German Britta Steffen's mark by nearly a third of a second.

But before she claimed the 100m world record for the third time, she had the most normal of life experiences.

Lenton admitted she had some pre-wedding dramas ahead of tying the knot with fellow swimmer Luke Trickett this weekend.

And while she was on cloud nine, the mere mention of her wedding made Lenton show what was important to her.

"I think the wedding is going to top everything," she said.

"I don't think you can really compare the two, it is a very special personal moment for me."

An ultra-relaxed Lenton, who claimed five gold medals at the Melbourne world titles, said she used the experience of swimming against arguably the greatest swimmer in history to her advantage.

She even trash talked the man who handed the world record line a regular beating at Rod Laver Arena on his way to four world marks and seven golds.

"I was trash talking him before, asking what he has got and telling him if he is going to bring it tonight," she joked.

"I honestly think he was a little intimidated by me. I think deep down he was really scared of me.

"Before the race he said good luck and he is a good competitor to race against and I will remember that for the rest of my life that I raced against Michael Phelps.

"I think I held my own this week."

There was speculation Lenton's swim would not count because of the unusual nature of her racing against Phelps and that he could be seen as pacing the Queenslander.

However Swimming Australia chief executive Glenn Tasker expected the swim to be ratified as a world record after talking to key officials at the sport's governing body, FINA tonight.

"The rule states about pacing, so if it was a fair dinkum race off the gun then there is no reason why the world record will not be ratified," he said.

"We have been told to submit the forms and all the details and they cannot see a reason why FINA will not ratify it."

The fact she had Phelps leading her out could prove controversial in the eyes of some but Lenton also had to deal with the heavy wash across her lane produced by the superfish.

That Phelps swam a very respectable 48.72s should help Lenton's case.

Lenton's coach Stephan Widmer said she only discovered she was swimming against Phelps some 20 minutes before the dream marketing showdown between the world's best male and female swimmers.

The only surprise was that Phelps, for once, was upstaged.

The all-conquering American team comfortably won the battle of the swimming superpowers for the third straight time, 181.5 to 129.5.

The Australian women toppled their counterparts but the men were pummelled.

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