A clinical hat-trick from winger Mateo Carreras helped hoist Argentina into the World Cup quarter-finals with a 39-27 victory over Japan in a winner-takes-all Pool D shootout at Stade de la Beaujoire on Sunday.
Argentina's Santiago Chocobares scored a try after 67 seconds but that served only as an appetiser for a thrilling contest between two well-matched teams playing for the right to take on Wales in the last eight in Marseille next Saturday.
Emiliano Boffelli also crossed for a try and contributed nine points from the kicking tee for Argentina as the twice World Cup semi-finalists returned to the knockout stages after missing out in 2019.
"It's been so competitive, everyone's fighting for their lives," said a relieved Pumas coach Michael Cheika.
"We gave them a few easy entries back into the game but you look on the positive and if we can turn that around next week, maybe we'll be a chance."
Japan, whose run to the quarter-finals on home soil four years ago captured the hearts of a nation, head home despite a battling performance and tries from lock Amato Fakatava, scrumhalf Naoto Saito and replacement winger Jone Naikabula.
"I guess as a coach you can't ask for much more," said Jamie Joseph, whose seven-year reign as Japan coach ended with the defeat.
"My boys gave everything, they are behind me breaking down crying. We conceded some soft tries, that's the hurting part, but it will go away with time."