Defending champions Spain could be knocked out of the World Cup Wednesday if they crash and burn against Chile at the Maracana stadium, the spiritual home of the Brazilian game.

Humiliated 5-1 by the Netherlands in their opening Group B game, the 2010 winners and two-time European champions, will be doomed if they lose to Chile and the Dutch avoid defeat to Australia earlier in the day in Porto Alegre.

Only three defending champions have previously fallen at the first hurdle -- Brazil in 1966, France in 2002, and Italy in 2010.

No defending champions have ever been eliminated after only two games of the first phase, putting Spain at risk of the earliest exit in history.

"Chile are a difficult team because we'll have to defend and we'll have to fight one against one," said Spain midfielder Andres Iniesta, scorer of the decisive extra-time goal against Holland in the 2010 final.

"We must be able to make the right passes, and look for those in space, so we can score goals."

Chile won 3-1 against Australia in their first game and coach Jorge Sampaoli has admitted that Spain's capitulation to the Dutch will influence his side's approach to the game.

"We had already developed a system before the World Cup and we already knew how we'd play against Spain," said the Argentine, whose side have lost only twice in their last 16 games.

"Obviously after watching Spain against Holland, we've considered minor changes, but Spain didn't deserve such a defeat."

He cautioned: "Don't forget they lost against Switzerland in their opening game at the last World Cup, but still became champions."

Sampaoli will wait until just before kick-off at 4pm (1900 GMT) before deciding whether to hand a start to Juventus midfielder Arturo Vidal, who is recovering from knee surgery and managed only 60 minutes against Australia.

Australia manager Ange Postecoglou thinks attack will be the best form of defence for his side as they face in-form Dutchmen Robin van Persie and Arjen Robben, who both struck twice against Spain.

"We know we have to be strong defensively, the Dutch are dangerous going forward, as they showed against Spain," he said.

"We know that Van Persie and Robben will be a challenge, but we knew that coming into the tournament. In saying that we also need to be attack-minded, we can't just defend for 90 minutes."

Netherlands coach Louis van Gaal has told his players to keep their feet on the ground after the euphoria of avenging their defeat to Spain in the 2010 final.

"You win the World Cup by winning the final," said the future Manchester United manager.

In Group A, Cameroon and Croatia, beaten by Mexico and Brazil respectively in their openers, meet in Manaus where defeat for either side will mean the end of their last-16 hopes.

Croatia are still bitter from their opening loss to Brazil in which they had a goal controversially disallowed while the hosts won a dubious penalty.

Meanwhile, Mexico goalkeeper Guillermo Ochoa was basking in the plaudits after a string of fine saves ensured a 0-0 draw against Brazil on Tuesday.

"It was the best game of my life," said Ochoa, 28, after he produced several stunning stops to frustrate Brazil at Fortaleza.

One stop in the first half, down low to his right to keep out Neymar's header, had shades of a legendary save by England's Gordon Banks to deny Pele in the 1970 World Cup in Mexico.

But the draw was greeted with howls of anguish by Brazil's media, with the Folha de Sao Paulo newspaper describing the performance as a "horror show."

"Brazil played badly. It's their worst start since 1978 and sows doubt as to their ability to face the big (teams) at the World Cup," the paper lamented.