Tim Cahill's towering header has given Australia hope of pulling off an upset in their opening World Cup game, having reduced Chile's early two-goal lead in Cuiaba.

It took just 11 minutes for the South American side to get their tournament up and running courtesy of Alexis Sanchez's goal from close range following an Eduardo Vargas knockdown.

Two minutes later La Roja doubled their lead when Vargas's run across the box left Jorge Valdivia in space to place the ball into the top left corner of the net.

It looked as though Australia were going to be in for a long night, but striker Cahill reduced the deficit on the 35-minute mark when he outjumped Gary Medel to make it 2-1.

Cahill very nearly found the net once more before the interval when Mathew Leckie prodded a ball through to him, but his angled drive was well kept out by Claudio Bravo.