Australia coach Arnold saw his Olyroos team strike a major victory for the underdog with their Tokyo 2020 success in Sapporo, where goals from Lachlan Wales and Marco Tilio did the damage.

Although the Argentina team this year does not carry the same star quality as the 2004 and 2008 sides that featured Carlos Tevez and Lionel Messi respectively, the South Americans were expected to be on a high after their senior side lifted the Copa America trophy earlier this month.

Arnold's Australian troops were highly impressive in the Group C tussle, however, even though their coach still saw room for improvement.

"Nobody would have given us a chance apart from us. I've been visualising this performance for the last couple of weeks, I even visualised the score," Graham said.

"I believe in these boys and I believe so much in them that I'm not happy with our overall performance. I was happy with the work rate, the energy, but at times we turned over the ball too simply and too easily. We need to improve as we go on, and we will."

Arnold pointed to Australia having only one previous Olympic men's football win in the 2000s, a 5-1 win over Serbia and Montenegro in 2004 at the Athens Games.

"It's a great win, but we've done nothing yet. It's three points, we're off to a great start, the first win, but the important thing is improvement," the coach added.

"We didn't mention the name of the opposition, it's all about us. Sometimes when you mention a nation like Argentina's name, everyone just starts thinking of the players, Diego Maradona, Lionel Messi, and Copa America champions.

"It was more about focusing on ourselves for the last week and making sure all the players knew their roles, their jobs and building a lot of belief in the players that we could go out there and put in a good performance and win the game."

He vowed Australia were "here to compete for a gold medal" and offered up the victory to those locked down in Australia during the ongoing COVID-19 crisis.

"It was probably the last thing I mentioned to the players before they went on the pitch," he said. "Australia, New South Wales in particular, is going through a very tough time at the moment with COVID, with lockdown and I just said to the boys, 'A lot of families are locked down at home, let's put a smile on a lot of Australian faces tonight, give them a performance they will remember'.

"I really expect that a lot of people back at home who didn't give us much chance of winning before really enjoyed that. I expect we put a lot of smiles on a lot of faces ... for tonight anyway."