Coach Tony Popovic and goalkeeping coach Frank Juric pulled one of the great selection shocks by turning to 22-year-old Beach, in just his third cap, over captain Ryan.
The young gun pulled off eight saves - more than any other Socceroo at a World Cup - in one of the great goalkeeping performances at Vancouver's BC Place.
Those included a stunning fingertip save to turn Abdulkerim Bardakci's fierce first-half strike on to the post, and a diving effort to deny Real Madrid star Arda Guler's second-half dipping free kick.
"A couple of days ago the boss and keeper coach pulled me aside and told me that I'd be playing," Beach said.
"(They said) that I'd been performing really well, they have confidence in me, and that gave me all the confidence I needed to get out there and do my job.
"It was amazing. This is a dream come true."
In the process, Beach, like Nestory Irankunda and Paul Okon-Engstler, vindicated Popovic's faith - and will surely hold his spot for Friday's clash with the United States.
"They were maybe shocks for a lot of people, but not shocks within our playing group or staff," Popovic said.
"It's something that we've always seen, and I've got a lot of belief in the young man.
"He stood up today, so very happy for him."
Defender Alessandro Circati was also impressed by Beach's game.
"It's not easy to come in as a goalkeeper, to replace Maty, there's big expectations. I'm very happy for him," Circati said.
Beach said Ryan and Paul Izzo had given him a lot of support.
"They had some chats to me before the game, and were very calm, relaxed," Beach said.
"They just said, 'enjoy it out there, have fun, good luck, and go do what you do, everyone knows what you can do, so go do what you do, and play your game'.
"Maty and Paulie have been excellent. All three of us have been pushing each other for the last four or five weeks relentlessly every week."
Goal-scorer Irankunda said he was "super proud" of Beach.
"I know a lot of people weren't expecting him to start, and he came out today and he's shown the world what he can do," Irankunda said.
"He made a lot of important saves, and if it wasn't for him, the scoreline could have been different, but he saved us, he kept us in the game."
Aziz Behich, Beach's captain at Melbourne City, is well aware of his capabilities.
"I've seen his development over the last couple of years and he's only going up and up, and I think this is just the beginning for him," he said.
