Leisel Jones will be aiming to continue Australia's gold medal winning ways at the world titles in the 100m breaststroke final in Melbourne.

The world record holder was the second fastest qualifier behind American rival Tara Kirk but appears to have plenty left in the tank.

Young gun Emily Seebohm will chase her first medal at a major international meet in the final of the 100m backstroke.

The 14-year-old chopped almost half a second off the national record in last night's semi-finals to be the fastest qualifier ahead of the likes of Laure Manaudou and Natalie Coughlin.

One of the biggest races of the meet will also be in the men's 200m freestyle.

Superstars Michael Phelps and Pieter van den Hoogenband will duke it out alongside Korean youngster Park Tae Hwan and Australia's Kenrick Monk.

Australian team captain Grant Hackett returns to action in the heats of the non-Olympic 800m.

In last night's action, Libby Lenton picked up Australia's second gold medal by leading Jess Schipper in a 1-2 finish in the 100m butterfly.

Brenton Rickard and Stephanie Rice picked up bronze medals in the 100m breaststroke and 200m individual medley respectively.

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