Super sub Sam Kerr has come off the bench to score the clincher in front of her hometown fans in the Matildas' rusty 2-0 Olympic qualifier win over Iran in Perth.

Watched by 18,798 fans at HBF Park on Thursday night, Ellie Carpenter opened the scoring in the 19th minute before Kerr sealed the deal with her 78th-minute tap-in.

Matildas coach Tony Gustavsson warned on the eve of the match that he wouldn't be throwing his jet-lagged stars into the deep end, and a glimpse at the bench proved those words to be true.

Kerr, Mackenzie Arnold, Katrina Gorry, Kyra Cooney-Cross, Caitlin Foord, Steph Catley, Hayley Raso, Alanna Kennedy and Mary Fowler all started on the pine.

With the scoreline still just 1-0 at the 65-minute mark in a match Australia were predicted to win easily, Gustavsson brought on Kerr, Catley and Fowler in a triple substitution.

The move worked a charm, with the trio joining forces to create Australia's second goal.

Catley combined with Fowler for a one-two before firing a low pass across goal, allowing Kerr to complete an easy tap-in.

Foord, Raso, Arnold and Gorry were among the unused substitutes in a match Australia could have easily won 5-0.

"Mixed feelings," Gustavsson said of the win.

"This might have been one of the most challenging preparations I've had with this team. Very little prep time, a lot of jet lag.

"I do think we were rusty tonight. Normally our conversion rate is much better.

"We could have scored five or six goals considering what we created."

The Matildas enjoyed 82 per cent possession in the first half, and a neat run down the right from Cortnee Vine helped set up the opener.

Vine's cross made its way to Charlotte Grant, who passed it off to Carpenter to rifle the ball home for just her fourth goal in 70 appearances for Australia.

Carpenter almost had a second in the 31st minute when she was played in and only had the goalkeeper to beat, but her shot from an angle was well wide of the target.

Iran's players did their best to waste time whenever the chance arose.

Theatrical rolls on the ground were a common theme in the first half, much to the frustration of Matildas.

Adding to Australia's frustrations was their own inability to finish off their chances.

Local hero Kerr received a rousing reception when she was brought on in the 65th minute.

The star Chelsea striker fired a 72nd-minute strike over the crossbar, but she made no mistake from her tap-in six minutes later.

Kerr had a golden chance to score again in the 93rd minute, but she couldn't keep her strike low enough.

In the earlier match, the Philippines came from behind to post a 4-1 win over Taiwan, firing them to the top of the group.

Yi-yun Hsu opened the scoring for Taiwan in the 47th minute as the underdogs dreamed of a an upset.

But a double to Sarina Bolden and goals to Katrina Guillou and Chandler McDaniel meant it ended up being an easy win for the Philippines.

The Matildas face off against the Philippines at a sold-out Optus Stadium on Sunday, before returning to HBF Park next Wednesday to face Taiwan.

Australia must finish on top of the group to guarantee passage through to the final round of Olympic qualifying in February.