It may have taken a while for them to click back into perfect harmony but Celtic boss Ange Postecoglou is now eliciting the sort of dynamic performances from his old Socceroos charge Aaron Mooy that he always fancied he would.
Saturday at a drenched Hampden Park felt like the cement in the rekindling of the dynamic between the two Aussies as Mooy delivered all-action, tireless midfield patrolling amid sodden conditions to help propel Celtic to another Scottish League Cup final.
His tour de force in the 2-0 win over Kilmarnock was exactly the sort of display Postecoglou has been looking to squeeze out of the admirable 32-year-old - and exactly the sort of result Mooy came to a serial-winning club to savour in the twilight of his career.
"I came here is to compete for trophies," conceded Mooy, who's now in sight of winning his first trophy since guiding Western Sydney Wanderers a decade ago to the A-League Premiership.
"Celtic's a massive club and they've got a massive history and they are always challenging, so it's a big plus for players looking at coming here.
"I'm really enjoying my football just now, it's an amazing club to play for and I'm just trying to make the most of it."
Mooy did not exactly start by pulling up trees after Postecoglou, who had overseen about half of the midfielder's starts for Australia when he was the Socceroos boss between 2013 and 2017, snapped him up in the summer.
Postecoglou had been left impressed by Mooy's dedication to train alone and get himself fit to play in Australia's World Cup play-off win over Peru in June and was equally won over by his excellent performance in that game.
But after beginning slowly in Glasgow, Mooy's gradually got more and more influential as his match fitness has improved and, after a starring role for his country at the Qatar World Cup, he's returned fresh and hungry for a New Year silverware hunt.
As one of Postecoglou's key men now, his swirling free-kick on Saturday prompted the confusion that eventually ended with Daizen Maeda scoring their opener.
"The first goal is always important. I didn't actually see what happened, did Daizen put it straight in?" asked Mooy, in puzzlement, before grinning, "I don't think I get the assist but I'll claim it anyway!"