A distraught Tim Cahill broke down in tears as he spoke of the harsh red card that plunged his - and Australia's - World Cup stocks to the depths of despair.

"I'm just sad. It's probably one of the saddest moments of my footballing career," said Cahill who was sent off for his challenge on Germany's Bastian Schweinsteiger inside an hour of Australia's demoralising 4-0 thumping.

Cahill could scarcely believe it when Mexican referee Marco Rodriguez reached for a straight red card for his late but far from malicious challenge.

Trailing 2-0 at the time, and being outplayed all over the park, his dismissal scarcely affected the outcome of Australia's dismal opening match in South Africa.

But its real impact will be felt when Australia's number one player automatically misses the must-win second match against Ghana in Rustenburg next Saturday.

Wiping tears from his eyes, Cahill told reporters how he had deliberately pulled back in the tackle so as not to hurt his opponent, making contact with his knee rather than his foot.

His explanation could not have been more convincingly corroborated than when the Bayern Munich midfielder tapped him on the shoulder in passing and told him: "It wasn't a red card."

"To hear Schweinsteiger say that is very nice of him," said Cahill.

"It means a lot coming from him.

"It just shows you how dreams can be made and then crushed in the space of hours, or seconds.

"My leg stayed bent all the way on purpose.

"I never once tried to straighten it.

"I didn't hurt the guy.

"What do you want me to say?"

The Socceroos can ill-afford to be without their number-one player in such dire circumstances.

But Cahill, the hero of Australia's 2006 World Cup in Germany, intends to play as much a part as he can.

"Definitely I can pick myself up," he said.

"I am 100 per cent committed to the cause.

"I am 100 per cent behind the lads.

"I'll train just as hard to prove my worth if I can be available for the last game (against Serbia on June 23)."

Cahill said German midfielder Mesut Ozil was the "devastating factor" in Germany's bravura performance.

"The way he opened things up was a massive credit to him," Cahill said.

"He is a great player and obviously he's going to do great things for his team.

"He is someone who will go far."

Cahill refused to criticise coach Pim Verbeek's surprising last-minute strategic changes which involved several reshuffles and had Cahill at one stage playing in the unusual position of lone striker.

"If I played left back it wouldn't bother me," he said.

"It's an absolute privilege to play for my country."

Despite his deep hurt, he tried to be philosophical.

"The beauty of football," he said, "is that one day you're a hero and the next you're at the bottom."

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