Down 1-0 to a ruthless Melbourne Victory and on the ropes with 15 minutes to play, the midfielder replaced Mickael Tavares at AAMI Park as the Sky Blues chased the game.
As is well-documented, it was to no avail as Kosta Barbarouses and Leigh Broxham added late goals to Besart Berisha's first-half opener.
It's an experience Antonis recalls as he and Western Sydney Wanderers prepare to travel to Brisbane for Friday night's elimination final showdown.
And the 23-year-old is hoping that tough lesson of two years ago aids his quest to help take the three-time grand finalists all the way.
"I was unlucky I didn't get to win the grand final that year (with Sydney), but hopefully this year we do," Antonis said.
"Finals are always difficult. You don't get another chance - there's only one chance and that's it.
"It's crazy because anything can happen."
The Wanderers understand this well after last season's semi-final against the Roar, an absurd 5-4 semi-final win that will forever be remembered as one of the greatest games in the competition's history.
At Pirtek Stadium, Tony Popovic's men executed a startling comeback from 3-0 down that culminated in Dario Vidosic's extra-time winner.
In the sudden-death rematch, the Roar will hold the home advantage at Suncorp Stadium.
John Aloisi's dark horses are also riding on the momentum of their own final-round fightback from two goals down to seal a 4-3 home win over Wellington.
But Antonis, a likely starter on Friday, warned the Wanderers' interstate rivals not to underestimate their own recent run of form, hampered only by last week's AFC Champions League loss to FC Seoul.
"The boys are pumped, it's a big week," he said. "We're playing good football so we just need to keep it going.
"They're a good side but ... when we're on our game it's going to be difficult to beat us."
Antonis has been a revelation since arriving on loan from Greek outfit PAOK in January, his recent midfield partnership with Kearyn Baccus keeping even captain Dimas on the bench.
He was reluctant to address his future beyond this season - his contract with PAOK runs until 2018 - though is happily thriving under Popovic's set-up.
"I'm feeling really good, the boss has got me into good shape," Antonis said.
"I'm starting to play really good football though I've still got much more to do, there's still a long way to go.
"I'm not thinking too far forward. At the end of the season that decision will come around but at the moment we're concentrating here."