A Johan Vasquez header from a set-piece gave Mexico the lead in the 28th minute, and the much-changed team held on successfully despite a better second half from the Socceroos after a shaky start.

Mexico coach Javier Aguirre made nine changes from the starting 11 that beat Ghana 2-0 in a friendly in Puebla last week.

There was much to like about the performance of the fringe line-up, barring a howling mistake in defence that should have cost an equalising goal in added time before the main interval.

A long ball forward put Mexico in disarray, with a poor clearance going straight to Mohamed Toure on the edge of the area as goalkeeper Raul Rangel charged off his line.

But the Socceroos striker volleyed wide with an empty goal at his mercy, drawing a collective gasp from the pro-Mexico crowd of 78,479.

That was Australia's only genuine chance in an opening half in which it was generally under siege.

Chavez blazed over from long range in the 10th minute, and goalkeeper Mat Ryan had to make a fine save 15 minutes later when he tipped a close-range header from Alexis Vega over the bar.

The pressure finally told as Vega swung in a corner and Vasquez soared over Aiden O'Neill to thump in a header off the left post.

Simulating 2026 FIFA World Cup conditions, the friendly included mid-half drinks breaks, but their timing – the first in the 32nd minute and the second in the 79th – appeared confusingly ad hoc.

The teams were also permitted 11 substitutions for the friendly, compared with six for a regular FIFA World Cup match, and they made liberal use of the quota.

To the delight of Mexico fans, Aguirre replaced Rangel with 40-year-old stopper Guillermo Ochoa for the second half, then triggered five substitutions on the hour-mark, including rising 17-year-old attacker Gilberto Mora.

Australia coach Tony Popovic followed suit with four changes eight minutes later, and was nearly rewarded immediately when substitute Kai Trewin's through-ball found Ajdin Hrustic in the area, only for the midfielder to slam his shot straight into Ochoa.

On 76 minutes, Mexico had a goal disallowed from a free-kick taken much too quickly for the referee, triggering a heated exchange between the teams before the kick was re-taken.

But it made no difference to the final scoreline as Mexico ran out the winner.

Socceroos coach Popovic said he was happy with his side’s performance, despite the defeat.

“I’ll take having clear chances like that in every game, two of those, because our opponent didn’t have that,” he said.

“We lost the game, but it’s a very good hit out for us. I’m happy we could play this match. We’ll learn a lot. We’ll grow from this, from the game.”

Australia defender Harry Souttar, a hero of the 2022 FIFA World Cup in Qatar, played his first international since 2024 after prolonged achilles tendon injury trouble, but attacker Cristian Volpato missed out on a Socceroos debut after his surprise switch from Italy.

“Fitness-wise, Harry Souttar gets minutes, Matthew Leckie gets minutes, Jackson Irvine gets minutes. So we took a lot of things, not just football-wise, but physically we needed to gain something today,” Popovic said.

Souttar said Australia would work on its set-piece defending before its final warm-up game against Switzerland on 7 June (AEST) in San Diego.

"To concede off a set-piece was disappointing," the Scotland-born Leicester City centre back said.

"It was disappointing to lose, particularly at the end but there were plenty of positives to take from it."

“I think the kind of proof is in the second half performance.

“Jacko [Jackson Irvine] said it as soon as we came to the dressing room there, that’s what we’ve got to be, starting from the first whistle. We can just take that forward.”

Souttar's team-mate and Socceroos midfielder Aidan O’Neill agreed.

“Yeah, we’ve learned a lot from that first half,” he said.

“I think there’s maybe a few boys that haven’t played an atmosphere like that before. So, yeah, it’s all learning.

“I think the second half we were outstanding. I think first half they were better. The second half, I think there’s no doubt we were the superior team, we played great football as well, offensively and defensively.

“I can’t actually remember a chance they had on goal and the chances we had speak for themselves as well.”

Even Mexico coach Javier Aguirre acknowledge Australia's improvement in the second period.

“I thought they were going to play more openly in the first half," he noted. 

“In the second half, I think they also had the ball, they played well, what we expected, but defensively, their good defensive work surprised us.”

Mexico opens the 2026 FIFA World Cup on 12 June (AEST) against South Africa in Mexico City before playing Korea Republic and Czech Republic.

Australia starts its campaign against Turkey on 14 June (AEST), then meets co-host United States before playing Paraguay.