Michael Phelps has claimed his third world record in as many days, burning up the pool at Rod Laver Arena in the 200-metres individual medley.

Phelps continued his memorable week in Melbourne with another stunning swim in Thursday night's final, well under the world record split for each discipline with the backstroke leg the American's best of the four strokes on the night, winning in the time of 1:54.84, 1.21 seconds ahead of fellow American Ryan Lochte with Hungary's Laszlo Cseh in third.

With four gold from the meet so far, Phelps is on track to create history as he is gunning for seven gold from this world championships and in the rich vein of form that he is in at the moment it is going to take something special to get the better of Phelps.

The United States once again set the pace. Leila Vaziri equalled her world record from the night before to win the women's 50-metres backstroke. The 21-year old has made an impressive international debut in this event after failing in her pet event, the 100-metres earlier in the meet, proving that her semi-final swim was no flash in the pan, winning in a time of 28.16 seconds ahead of Aliaksandra Herasemenia of Belarus with Australian Tay Zimmer in third.

Just as impressive as Phelps was the simply stunning performance of the United States in the women's 4 x 200-metres relay. Natalie Coughlin's incredible opening leg set the foundation of the American's world record, overtaking early leader Libby Lenton of Australia in the third of her four laps to hand the Americans a handy lead by the end of the first leg. Dana Vollmer and Lacey Nymeyer also swan superbly to extend the lead making the gold America's for the taking by the time Katie Hoff dived in the pool. The American's smashed Germany's old world mark to win in a time of 7:50.09, more than three seconds ahead of the Germans with France coming in third.

The men's 100-metres freestyle provided the 12th edition of the FINA World Championships with it's first dead heat with Canada's Brent Hayden sharing the spoils with defending champion Filippo Magnini of Italy. In one of the most thrilling finishes possible, six of the eight competitors lunged for the wall almost simultaneously with only 0.20 of a second separating the two winners from sixth placed Pieter van den Hoogenband. Eamon Sullivan, the man tipped by many to be the rising star of Australian swimming, surprised many with his bronze medal and Brazilian Cesar Filho Silva shocked the field by leading at the turn and eventually finished a very credible fourth.