Felipe Contepomi studied to become a doctor while playing rugby in Ireland, but admits the thought of coaching against his old mate Joe Schmidt is a daunting task.
A friendship forged from their days in Ireland will be put on hold when the Wallabies host Argentina in Townsville on Saturday.
Both sides arrive with momentum, Australia fresh off a 1-1 tour of South Africa while Los Pumas beat the All Blacks at home for the first time a fortnight ago.
Rankings points also come into play, with the sides effectively battling for the No.6 spot ahead of December's 2027 Rugby World Cup draw.
Contepomi, an 87-Test Pumas star who studied at the Royal College of Surgeons while playing flyhalf for Leinster, says all bets are off.
"I like watching his teams. I don't like playing against his teams," he said on Thursday.
"He's a brilliant coach. I have loads of time for him. A guy I keep in contact with.
"Sometimes when you hear he's leaving (as Wallabies coach next year) you think, 'You need to stay around for the good of the game'.
"He's so detailed. He'll have a trick or two, or three, under his sleeve."
Schmidt laughed when told of his opposite's remarks.
"That makes me a little bit afraid of what he's got cooked up and I hope he's not sleeping well about what we might have in our armoury," he said.
"I rate Felipe really highly as a coach and he's a good bloke.
"Those two things mean I hope the best for him, when he plays other teams. Not against us on Saturday, that's for sure."
