The Olyroos have earned their first point of their Olympic football run with a 1-1 draw against Serbia in Shanghai.

The team's coach Graham Arnold expects the adrenaline to kick in when his team go head to head with the defending champions Argentina, in their second group match this Sunday.

VIDEO: Olyroos draw with Serbia

"The adrenaline will kick in for sure when they go and play Argentina in a couple of days," Arnold said.

"Tomorrow will be about recovery and a light training session, and we're ready to go again - that's the beauty of this competition."

Australia's Ruben Zadkovich failed to find the back of the net, after his goal was rejected by Slobodan Rajkovic, as the Olroos became the first Australians in action at the Olympics.

Australia should have had gone 2-0 up but substitute Billy Celeski's 74th-minute shot hit the post.

Arnold believed his players would pull up well, despite playing in very hot, humid conditions.

"It's the same for all teams and our players are as fit as they have been probably in their careers," he said.

"I probably will make a couple of changes because the players put a lot of energy and effort into tonight.

"We've got 18 players."

Messi scored Argentina's first goal shortly before half-time and set up the winner.

Two minutes into the second half, Sekou Cisse brought the Africans back into the game when he beat Pablo Zabaleta in the air to head home the equaliser.

But Lautaro Acosta was perfectly placed to score the decider when Messi's shot on goal five minutes from time was parried by Vincent Angban.

Messi took to the field immediately after Australia's match at the same venue despite his club, FC Barcelona, winning the right through the Court of Arbitration for Sport to stop him playing.

Barcelona, who wanted the 21-year-old for their early Champions League matches which clash with the Olympics, gave in at the last moment.