Dethroned world champion Grant Hackett says Tuesday's Duel in the Pool will be the first step in his mission to reclaim his position at the top of world swimming for the 2008 Olympics.

Australia will go in as major underdogs against the Michael Phelps-led United States in the match-race meet in Sydney.

But while both teams agree the duel - while hotly contested - will provide a bit of levity after the seriousness of the recent World Championships in Melbourne, Hackett believes it will carry added personal importance.

"It's going to be tough, there's no doubt I'm a little bit tired after this week," said Hackett, who finished seventh in the 1500m final on Sunday after conceding both his 400m and 800m crowns at the world championships.

"Emotionally and physically, it was very, very draining, but now I'm just going to start to take the positive steps forward.

"I feel there's a little bit of space between myself now and the World Championships, I can start looking forward and improving on my performances and getting excited about swimming again and trying to swim fast.

"And I guess swimming tomorrow is the first step in doing that on the road to Beijing.

"The Duel in the Pool is going to be interesting. It's not an ideal situation that I'm in, but the first step is important."

The US comfortably beat Australia 183-102 the last time the two team's clashed in California two years ago, and come into Tuesday's meet after topping the medal count among a flurry of world records in Melbourne.

Phelps won seven gold medals and broke four world records, but under the rules of the head-to-head meet, will only be allowed to swim in four events.

Australian swimming coach Alan Thompson said the format would perhaps even the playing field between the two teams.

"We acknowledge they're the No.1 team in the world, but it's a great opportunity for us to try and bump them off their perch," said Thompson.

Team captain Hackett added: "We're going in to the meet in the underdog position."

"Certainly seeing the way these guys swam at the world championships, the performances they produced were obviously outstanding, so for us we're in a chasing position.

"We certainly want to get up and close that gap a bit more."

After claiming five gold medals in Melbourne, Libby Lenton will spearhead Australia's women's team.

"Obviously the American team is so strong, and it's always great to compete against the team that's the best in the world at the moment," said Lenton, who is also planning her wedding this week.

US swim coach Mark Schubert said even he had been surprised by his team's stunning success in Melbourne.

"We swam very well, and probably surpassed our expectations in a lot of events," Schubert said.

"Tomorrow, you're going to see the two best swimming nations ... and get the chance to see them swim against each other, it might be an unprecedented opportunity."

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