Chile held off an Australia fightback to open their World Cup campaign with a 3-1 win over the battling Socceroos in Cuiaba.

The South Americans had threatened a rout after goals from Alexis Sanchez and Jorge Valdivia in a whirlwind opening 15 minutes at the Arena Pantanal.

But Australia, the Group B outsiders, showed fighting spirit to reply through inspirational veteran Tim Cahill and they went close to equalising before Jean Beausejour secured the points in stoppage time.

Spain's surprise hammering earlier in the day potentially opened up a route through the group for the highly rated Chileans, and they began as if it was all too easy.

Australia, by contrast, were ragged and cut open with regularity in the early stages. Their goal was breached for the first time in the 12th minute.

Challenges were few and far between as Sanchez found Charles Aranguiz and he was allowed to cross for Eduardo Vargas.

Vargas failed to make clean contact with his header but Australia failed to clear and Sanchez calmly picked his spot and lashed home from six yards.

Chile doubled their lead less than two minutes later as they powerfully swept forward once again.

Sanchez brilliantly turned Mile Jedinak and raced into space as Vargas drew the defence with a well-timed run.

He picked out Valdivia on the edge of the box and the finish, into the roof of the net, was clinical.

The game seemed beyond Australia at that early stage and Chile looked likely to increase their lead as they maintained their tempo for much of the opening half-hour.

But Australia gradually began to settle and Cahill dragged them back into the game with a trademark header.

Chile captain and goalkeeper Claudio Bravo invited pressure with a poor clearance. His defence did appear to repel any threat but Ivan Franjic won the ball back for Australia, exchanged passes with Mathew Leckie and whipped in a dangerous cross into the area.

Former Everton star Cahill timed his leap perfectly to plant a firm header past Bravo.

The game then opened up considerably.

Mauricio Isla was released by a fine pass from Vidal but was denied by a superb challenge from Jason Davidson.

Early in the second half Cahill headed past Bravo once again, from a Leckie, cross only to be frustrated by an offside flag.

Bravo produced a brilliant save to keep out a powerful first-time shot from Mark Bresciano from a Davidson cross.

Play switched quickly to the other end where Alex Wilkinson cleared off the line after Vargas dinked the ball over Maty Ryan from another defence-splitting Sanchez pass.

Bresciano continued to get forward from midfield in search of an equaliser and fired wide. Cahill's presence in advanced positions also gave Chile continuing problems.

Cahill appealed for a penalty after going down in a challenge from Gonzalo Jara with two minutes remaining but nothing was given.

The task proved beyond the Socceroos and substitute Beausejour, of Wigan, wrapped up the scoring after Ryan saved from Mauricio Pinilla.