The 21-year-old was part of the Socceroos Asian Cup squad, but did not get the nod to play for the side that eventually won the tournament.
Antonis said: "I was ready and waiting for the moment that the boss said 'You're in', so I just kept working and working until the coach said something. I was a bit upset not to play but at the end of the day, I was there to learn, to experience everything and be part of the squad and take everything I can from it. My job was to be ready the moment I was thrown in. It didn't happen but that's football.
"There were some really tough physical sessions and some very intense tactical sessions. Overall, it was a great experience. I learned so much on and off the field. Being able to see what the national team does is a huge thing.
"Over the whole month, I think I picked up something almost every day. It's pretty hard to isolate one thing because it was all at such a great level. I'll be taking that experience back with me and be working on my weaknesses and making myself better."