With Alanna Kennedy (quad) and Clare Polkinghorne (rested) unavailable, Gustavsson turned to 17-year-old debutant Jessika Nash and 19-year-old Courtney Nevin, in her sixth cap, in the centre of defence against the world champions.

A record home Matildas crowd of 36,109 fans packed Stadium Australia but were silenced after just 24 seconds when Ashley Hatch pounced on defensive lapses from both Nevin and Nash to snatch the lead, in a baptism of fire for the young defensive pairing.

"We need depth in the back line and we need to look at players and be brave enough to actually get them into these types of games," Gustavsson said.

"Normally, if this was 15 years ago, and I was coaching, I'll probably give them 10 minutes at the end when you'd either won or lost the game.

"But those minutes are not at the same value as warming up, record crowd US in front of you, in the stadium that is going to hold the World Cup final.

"(For them to) be able to deal with that in that environment is what we need, and I'm going to have their back all the time."

Nash was substituted for right-back Charlotte Grant at halftime but Gustavsson said that was a pre-planned move to test Ellie Carpenter out at centre-back.

Just four minutes later, Margaret Purce cleverly outbodied Nevin, then cut the ball back to Rose Lavelle, who coolly doubled the US' lead.

Skipper Lindsey Horan added a third from the penalty spot in the 68th after she was fouled by Carpenter.

But the US far from had it all their way, especially in the first half, with goalkeeper Casey Murphy stepping up to deny Australia at every turn on debut.

In the 33rd minute, Sam Kerr forced a top-drawer save from Murphy with a brilliant, powerful effort, while just before halftime, Caitlin Foord's fierce shot forced a second big save at full-stretch from Murphy.

But the biggest chance came in the 38th minute when Simon spurned a gilt-edged oppurtunity, blasting a close-range effort over the bar after Foord's terrific run and cut-back.

"As a striker, you pride yourself on scoring goals and I take full responsibility that I should have finished that," Simon said.

"The game (would have been) 1-1 at that point, so that could definitely change the momentum of the game.

"The game was won and lost in the 18-yard box. Unfortunately, that was our downfall today."

Gustavsson had treated the game as a dress rehearsal for a World Cup final and stressed while the Matildas were caught out on transition at times, he wouldn't change his approach.

"We are not going to change the way we play," he said.

"This is who we are. This is what we're about and we need to learn to do it better.

"And we need to do that against the best teams because that's when you get exposed. If you don't play against the best team you might not get exposed to those kinds of scenarios."

Australian Associated Press