The Australian Swim Team has claimed gold in the 4x100m Mixed Medley Relay at the FINA World Championships on Wednesday night, storming home in a nail-biter to beat the United States by two one hundredths of a second.

The team of Mitch Larkin (backstroke), Matthew Wilson (breaststroke), Emma McKeon (butterfly) and Cate Campbell (freestyle) clocked 3:39.08 to take the top honour in the new Olympic event ahead of the Americans (3:39.10) and Great Britain (3:40.68).

NSW Institute of Sport athlete Matt Wilson put in a fantastic split time in the breaststroke leg to give the Aussies the best chance of success.

Recording an incredible split of 51.10 in the final leg, Campbell then brought the team home to give Australia its third gold medal of the championships.

Earlier in the meet Bronte Campbell swam the freestyle leg during the heats of the event.