Lionel Messi does not find much complicated on a football pitch. But he did against the Socceroos.

Messi's mercurial abilities loomed large in Argentina's 2-1 win which knocked the Australians out of the World Cup in Qatar.

The Argentine captain scored a glorious goal and was acclaimed as player of the match.

But after his team went 2-0 up, the gallant Socceroos made a late charge.

"Things got complicated in the end with their goal," Messi said.

"But it's a World Cup. And it's never easy."

Socceroos substitute Craig Goodwin fired an audacious long-range attempt in the 77th minute which deflected into the net from Argentina's Enzo Fernandez.

The own goal sparked the Australians, who had two more golden chances, with Aziz Behich and Garang Kuol coming close to equalisers in a frantic finale.

Messi was not surprised.

"It was a very difficult match, we knew it was going to be this way," he said.

"We knew it was going to be a very physical match and they were very strong.

"We had the game under control and could have scored another one - we were almost punished for it in the last minute.

"There were a few scary moments ... it was a tough game, a tough day.

"We're through, that's the important thing."

Agentina next meet the Netherlands in next Friday's quarter-final (0600 Saturday AEDT) as Messi seeks to capture the World Cup at his fifth attempt.