The 27-year-old started in place of Arnold in the 2-1 loss to Brazil on the Gold Coast on Sunday night and made four cracking saves to deny the visitors.
Micah is one of eight Matildas returning to European clubs on Monday and won't be part of the two friendlies against Taiwan starting on Wednesday.
Arnold, who plays for Portland in the US, will remain with the squad. She was in goal for the 3-1 loss to Brazil in Brisbane on Thursday.
Micah was Australia's goalkeeper at the Tokyo Olympics in 2022 before a serious concussion kept her out of the 2023 World Cup.
Arnold, one of the Matildas' heroes in the charge to the semi-finals, took her chance and has been preferred ever since.
Micah can keep the heat on with strong club displays.
"One thing I have learned over the course of my years in the Matildas is that the No.1 is never really set. It is always about the most recent performances," Micah said.
"I feel like I'm training really well and feeling good at my club in Liverpool so that helps as well."
A permanent coach will replace interim boss Tom Sermanni in the near future, which will open another chance for Micah to impress with a clean slate ahead of the 2026 Asian Cup in Australia.
"I think it is a fresh leg (up)," Micah said.
"A lot of people haven't played in our team for a long time so it is good to see a lot more rotation and players stepping up."
Sermanni said it was only a positive that Micah, who had not started for almost a year in the national side, was back in form and in the frame to push Arnold.
"They are two very good goalkeepers playing in the two top leagues in the world and at two very good clubs," he said.
"There is obviously competition there and we have young Chloe (Lincoln) coming through as well. That's a positive thing for us."
Matildas stars Caitlin Foord, Hayley Raso and Steph Catley are among players on the way back to Europe.
Australia will now meet Taiwan in Melbourne on Wednesday and again in Geelong on Saturday.
"We've had eight players leave so we have a limited squad but I think it is an opportunity to look at players who have not been starters and not been in the national team to see how they play," Sermanni said.
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