Chile helped pile the pressure on champions Spain after sealing an eventually comfortable 3-1 win over Australia in their World Cup Group B opener in Cuiaba on Friday.

Early goals from Alexis Sanchez and Jorge Valdivia put the South Americans in front before Tim Cahill's brilliant header gave the Socceroos a lifeline, only for Jean Beausejour's fine injury-time strike to seal the victory.

The result meant Spain have a lot of ground to make up following their 5-1 trouncing by the Netherlands in the earlier Group B match.

Although Chile dominated much of the opening stages, they came under pressure at times from the battling Aussies in the second half, with Cahill having another stunning header disallowed for a marginal offside.

Barcelona star Sanchez got Chile off the mark on 12 minutes with a precise strike inside the near post from close range after Australia failed to clear a cross into their box.

Valdivia's second barely 90-seconds later was a peach as he curled home from outside the area.

Australia weren't prepared to give up and Cahill soared to head into the top corner 10 minutes from time.

But Beausejour's drilled low effort from distance put Chile level with Holland on three points meaning Spain will almost certainly have to beat the South Americans in Rio on June 18 to avoid the ignominy of an early elimination.