Mooy swapped Huddersfield Town for Brighton at the start of this month in a season-long loan deal.
The midfielder made his debut for the Seagulls in their 1-1 draw with West Ham in the second round, coming off the bench in the 85th minute. He was an unused sub in their 2-0 loss to Southhampton on the weekend.
Mooy's move to Brighton reunites him with Ryan, his Socceroos teammate and fellow Westfields Sport High School graduate. The Aussie pair both went to the Fairfield school and played together in the Westfields' side in their junior years.
Westfields have produced a number of current and past Socceroos over the years including Harry Kewell, Jason Culina, Milos Degenek, Danny Vukovic, Matt Jurman, Bernie Ibini, Mustafa Amini and Terry Antonis.
More than a decade after sharing the same field in western Sydney, they have been reunited in East Sussex in England’s top flight. And Mooy admits he's happy to have a familiar face at the Seagulls.
“It’s going good, I’m enjoying it,” he told The World Game.
“It’s obviously good to have Maty here, I know him well. He’s helped me settle in. We went to Westfields, the same school, for a few years and then the national team as well.
“He was in the year below me, but we played and trained together at school a fair bit. I’ve known Maty for a long time.
“It’s weird that we’re at the same club. What are the chances?”
Mooy says the appeal of staying in the Premier League, and working under new manager Graham Potter, attracted him to joining Brighton from the Terriers.
“Obviously I wanted to stay in the Premier League and Brighton gave me an opportunity and I thought it was a good fit for me as well. The way the manager wants to play and hopefully I can help the team,” the midfielder said.
"The move happened quite fast and late in the window. I’ve only been here two weeks and a bit, so I’m just settling in.
"It was good to get on the pitch [against West Ham] – even five minutes was nice.
“I’m enjoying it, the training’s really good. Lots of games in training, which is what I like. He makes you understand what he wants, it’s very clear.”
Brighton are pushing to finish in the top half of the table this campaign after battling relegation in the past two years.
They have made a solid start to the season, undefeated after the first two matches with a 3-0 win over Watford followed by the draw against West Ham, before going down 2-0 to Southhampton.
The Seagulls currently sit in eighth spot on the ladder and face reigning champions Manchester City away on Sunday.
