Australia's powerful women's 4 x 100 medley relay team produced the highlight of the penultimate night of the 12th FINA World Championships, with another world record in Melbourne.

In a team filled with proven stars and world champions in their chosen discipline, the big story for the locals was the the breakthrough performance of 14-year-old backstroker Emily Seabohm. Seabohm, swimming the first leg, was always going to be the weak link for the Australians but swam the race of her life to take up the challenge to in-form American Natalie Coughlin.

When Seabohm hit the wall in third place only 0.13 of a second behind the United States and Japan the Aussies were in the box seat. Leisel Jones' second leg was where Australia had the race won and the record in sight. Tthe current world champion in the distance was cool, calm and ruthless and almost immediately put a gap between herself and the rest of the field, Jones turning a slight deficit into a substantial 1.30 second lead.

United States butterfly swimmer Rachel Komisarz swam a strong leg against Jessicah Schipper but the Australian did well enough to keep the lead at over a second, meaning that Libby Lenton, anchoring the team, was swimming against the clock, handing the Aussies gold in a world record time of 3:55.74 with the United States and China taking the minor medals.

Michael Phelps is still on target for an incredible eight golds in Melbourne but was made to fight hard for gold number six, coming from behind against compatriot Ian Crocker in the 100-metres butterfly. This event was always going to be Phelps's biggest challenge, with Crocker a genuine star over the distance, and he had the measure of Phelps for 85-metres only for Phelps to finish the stronger in the final metres to record the time of 50.77. Venezuela's Albert Altes Subirates also swam strongly to take the bronze.

Kate Ziegler and Loure Manaudou produced an epic finish to the women's 800-metres freestyle with the American Ziegler pipping the Frenchwoman in a frantic sprint to the wall. Manaudou, gold medallist in the 200 and 400-metres, tried to swim Ziegler out of contention in the first half of the race with a lightning quick start and was well under world record pace after 200-metres, but Ziegler refused to be intimated by the pace of the Frenchwoman.

Manaudou started to drop her pace and the American pounced and the two were eyeballing each other and going stroke for stroke over the middle 400-metres. The last two laps became a sprint for the wall, Manaudou making the first decisive move breaking clear on the the penultimate lap to turn with 50-metres to just under half a second in front and looked to be finishing the stronger.

But Ziegler, the 1500-metres champion, refused to concede defeat and drew level again with 25-metres to go and finished the stronger, winning in a championship record time of 8:18.52 with Manaudou taking the silver in 8:18.80. Another American, Hayley Peirsol, was a further eight seconds behind in third.

Margaret Hoelzer continued the American gold rush to record the second fastest time in the history of the woman's 200-metre backstroke, taking the gold in a time of 2:07.16, finishing the stronger in her battle with reigning champ Kirsty Coventry of Zimbabwe. Coventry set the pace early, 0.33 of a second under world record time after the first 50-metres, but was unable to maintain such a cracking pace and by halfway Hoelzer had drawn neck and neck with the African and managed to maintain the ascendancy over the last two laps. Japan's Reiko Nakamura finished third with all three medallists recording personal best times.

The night also featured two 50-metre sprint finals. The United States went one-two in the mens 50-metre freestyle with Benjamin Wildman-Tobriner winning the gold in 21.88 seconds with compatriot Cullen Jones 0.06 seconds behind to take the silver and Swede Stefan Nystrand taking home the bronze.

In the women's 50-metres butterfly, European champion Therese Alshammar of Sweden won her first world crown when she nudged out reigning champion Danni Miatke. Alshammar won in a time of 25.91 seconds, 0.14 of a second ahead of the Australian with Inge Dekker of the Netherlands taking the bronze.

Phelps is withing touching distance of eight gold medals. Will he make it? We want your views at Sportingo.