Brilliant playmaker Nicolas Sanchez has emerged as one of the World Cup's elite talents and the key to Argentina's hopes of a semifinal upset, but he remains Public Enemy No 1 in the Wallabies camp over a diving furore earlier this year.
The Wallabies will renew hostilities with Rugby Championship rivals Argentina at Twickenham on Monday morning, with the victor booking a spot in next week's final.
But the Wallabies will be paying particularly close attention to the crafty goal-kicking first five-eighth, who sits second on the leading pointscorers at the World Cup with 74.
Sanchez is best remembered by Australian fans for his niggling tactics in the Wallabies' 34-9 victory in Mendoza in July, where tensions between he and Australian vice-captain Michael Hooper reached boiling point following a late try to Dean Mumm.
In the incident, Hooper had been running along in support of Mumm's charge to the tryline when he was held back by Sanchez - and retaliated by lashing out at the No 10.
The outstanding flanker swung around and struck the playmaker, who collapsed to the ground and clutched at his face before recovering to finish the game.
The Wallabies camp firmly believe there was an element of simulation about Sanchez's reaction - and have spent the week preparing for "flare-ups" in the match.
Prior to the start of the World Cup, World Rugby issued a crackdown on diving, saying it wouldn't be tolerated at the tournament and could lead to yellow cards and suspensions.
"I think it was a rule that was [introduced] before the competition started that there wasn't going to be any of that," Hooper said.
"It's not something that's crossing our mind, that's for certain."
Wallabies coach Michael Cheika has a strong bond with Argentinian rugby - he's good friends with champion halfback Agustin Pichot and current head coach Daniel Hourcade and came close to signing on as Pumas coach last year.
But he was understood to have been particularly unimpressed with Sanchez's actions, believing them to not have been in the spirit of the game.
The rigmarole which followed also angered the Wallabies, as Hooper was dragged into a judiciary hearing ahead of an all-important All Blacks showdown.
Hooper was initially slugged with a one-week ban, but an appeal was quickly lodged by SANZAR on the basis that it was too lenient - further enraging Hooper and the Wallabies, who lodged their own appeal insisting the ban was over the top.
Both appeals were dismissed and Hooper served the one-week ban in the Sydney club competition, before taking the field against New Zealand the following weekend - playing a key role in the 27-19 victory in Sydney which sealed the Rugby Championship.
Despite the dramatic fallout from his last clash with Argentina, Hooper says he doesn't needed any added motivation heading into the weekend.
"I don't think I need anymore fire than what's already [there] with the task at hand," he said.
"It's a World Cup semifinal and we want to win.
"It's what's at stake, that's what creates the passion. We're both proud nations, I know that.
"We're striving to be something that involves a lot of passion.
"We're going to stand up for what we think's right."
