The Six Nations champions kick-off off their Dove Men Series campaign against the Pumas without Triple Grand Slam scrum rock Adam Jones.
Wales will select an unfamiliar front-row today and Scarlets second-row Tomas Vallejos reckons South American can target the set-piece.
“We have massive belief in out scrum – it’s a foundation of our game and part of our rugby mentality,” said Vallejos.
“Adam Jones is a huge player for Wales and a top-level prop. But whether Wales are missing players or not the way we approach the scrum does not change. It will play a huge part of the game.”
Vallejos joined the Scarlets from Harlequins in the summer and arrived in West Wales last month, following the Rugby Championship.
He has settled into life at Parc y Scarlets and is relishing the opportunity to face his new-team mates but has already warned the Pumas of the threat posed by Rhys Priestland and George North.
“I’ve only been at the Scarlets for three weeks but the players that impressed me most when I arrived were Rhys Priestland and George North,” said Vallejos.
“Rhys is a very clever player and knows exactly what to do.
“George is a special player. What surprised me most with him is while he is a massive guy and physical he also has all the skills. The backs need to keep a close eye on him.
“There’s been a lot of joking from the Scarlets guys in the national team and we have been sending messages back and fore.
“It would be fantastic to beat Wales and it mean I have the bragging rights in the changing room and can have a joke with the players.”