It was a sobering opening chapter to the Tandy era, as the Pumas ran in seven tries at Principality Stadium to claim their biggest-ever win over Wales.
That might have been described as embarrassing or humiliating in years gone by, but such are the depths that Wales now inhabit that it felt bog-standard.
But while the scoreboard underlined the scale of the enormous task awaiting the new head coach, Tandy’s response was one of determination.
“I always knew it was going to be a challenge,” said Tandy.
“We're 12th in the world for a reason. We want to build something people can identify with and are excited about going forward.
“There's disappointment to concede 50 points and some of those were avoidable with concentration.”
Argentina’s attacking precision exposed Wales’ soft underbelly as well as their inexperience.
Geronimo Prisciantelli crossed twice, with Pedro Delgado, Simon Benitez Cruz, Mateo Carreras, Bautista Delguy and Santiago Grondona also on the scoresheet.
Fly-half Santi Carreras was flawless from the tee, adding 17 points to complete a clinical display.
For Wales, there were fleeting moments of hope amid the onslaught.
Tomos Williams, Dewi Lake, Jac Morgan and Blair Murray all touched down, while Dan Edwards and Jarrod Evans shared the conversions.
Skipper Morgan was outstanding before being forced off after scoring, and Louis Rees-Zammit’s blistering pace offered glimpses of promise following his return from an NFL adventure.
Yet despite the margin of defeat — Wales’ heaviest ever against the Pumas — Tandy focused on what he called “shoots of positivity.”
“The day ended in disappointment, but there's a lot to like around the group,” he said.
“You could see what we've done over the last two weeks coming out, to score four tries was a real positive and we left a few out there.”
The contrast in experience was stark: Argentina’s squad boasted 400 more caps than Wales, and their composure told.
But Tandy saw opportunity in the youthfulness of his side.
“We've got boys with low cap numbers, that's the opportunity for us,” he said.
“I know the journey we're going to go on, I'm excited and energised by it. I know today is the marker of how far we need to go. It's the line in the sand to probably give us something to work on.”
It was also a symbolic day for Tandy personally — the first Welshman to take charge of the national team since 2007, now swapping the away dressing room he once used as an assistant with Scotland for the home side’s.
Wales had broken an 18-match losing streak with victory in Japan earlier this year, but this defeat revived familiar frustrations in Cardiff, where they had lost their previous nine outings, including a 68-14 hammering by England in March.
Despite that history, Tandy’s faith in the project remains unshaken.
“We've been together as new coaches for two weeks. We've seen a lot of things we've worked on come out, but Test match rugby is unforgiving.
“We understand that, but I'm motivated and excited by this group.”
Hooker Dewi Lake, set to captain Wales for the remainder of the autumn after Morgan’s shoulder injury, echoed his coach’s balanced outlook.
“To concede 50 points in a game where we had some good defensive sets was disappointing,” said Lake.
“You could see the attacking game we want to play, the way this group wants to get the crowd into the game.
“Lapses of concentration or bounces of the ball can hurt you when you're playing a team that's sixth in the world and are as good as Argentina.
“It's always disappointing to lose the match but there were strides forward. We'll take the positivity out of today... it's about bouncing back ahead of the next one.”
Wales now turn their attention to Japan next weekend before facing the world’s top two sides, New Zealand and South Africa.
