Alexis Sanchez scored one goal and set up another to help Chile take a 2-1 lead at halftime of its opening Group B match against Australia in the World Cup on Friday.

A trademark headed goal by Tim Cahill in the 35th minute gave the Australians something to cling to after a first half Chile dominated at a muggy Arena Pantanal.

Justifying its tag as a dangerous outsider in the tournament, Chile went ahead in the 12th minute when Sanchez poked home a finish inside the near post after Australia captain Mile Jedinak failed to clear Charles Aranguiz's cross.

Australia's flimsy defense was opened up again barely a minute later, with Sanchez spinning his marker and laying the ball across for playmaker Jorge Valdivia to finish high into the net.