Izzo, 30, was selected ahead of Ryan and Joe Gauci and, in just his third cap, was the pick of the Socceroos' players in their 1-0 win over Canada in Montreal on Saturday morning AEDT.
Randers goalkeeper Izzo made two appearances and performed strongly in the previous international window against New Zealand, when Ryan was left out of the Socceroos squad to seal his move to Levante.
But ahead of the Canada game at Stade Saputo, Popovic told Paramount Plus Izzo also deserved a shot at the No.1 role with Ryan in the squad.
Izzo did more than just handle the occasion.
The goalkeeper, who played under Popovic at Melbourne Victory and Greek club Xanthi, underlined why the Socceroos boss rates him so highly.
Izzo made eight saves, the most of any Australian goalkeeper in a men's international, according to Opta, and looked assured throughout the match.
The 30-year-old marshalled his defence with aplomb, rarely looked flustered and proved a brick wall for the Canadian attack.
Izzo, who found out the night before he'd be starting, was delighted with his performance, acknowledging he'd felt "more at ease" with a couple of caps under his belt.
"I really wasn't expecting to play today, but given an opportunity, and I really wanted to take it again with both hands," he said.
When asked if his hope was to become No.1 ahead of Ryan, Izzo said "of course.
"Look, I think for me, it's hard to disregard the years and years and years of consistent work Maty's done for his country, let alone his club-land," he added.
"So for me, in respect of that, I have to work as hard as I can, because, to match Maty is no easy feat.
"And look, it's not like just something you can just take.
"So I really am just trying to put my best foot forward and take every opportunity that I get."
Izzo said he'd relished the "absolute chaos and carnage" of the closing minutes, which included a world-class effort with his leg to deny Jacob Shaffelburg in the 90th minute.
When asked whether Izzo could have risen to the challenge any better, Popovic was definitive.
"I think he answered the question with his performance," Popovic said.
He later added, unprompted: "Our keeper made some great saves as well, Paul Izzo, on some occasions.
"He's stepping up. Our captain, Matt Ryan plays at Levante wasn't selected for this game.
"So we're trying to increase the depth. And Paul Izzo showed that."
