The Pumas, who have failed to reach the knockout stages for the first time since 2003 after defeats by France and England, crossed for seven tries.

Joaquin Tuculet scored a first-half double after Nicolas Sanchez's opener.

The USA responded before the break when Blaine Scully touched down from fly-half AJ MacGinty's clever grubber.

But centre Juan Cruz Mallia crossed twice to reassert Argentina's dominance in the second half, with further scores from Jeronimo De La Fuente and Gonzalo Bertranou.

Paul Lasike responded with a try and Scully added a late third for the USA, who finish their campaign against winless Tonga on Sunday.

A third-place finish in the pool stages in Japan guarantees teams a place at the World Cup in France in four years' time.

Argentina: Joaquin Tuculet, Bautista Delguy, Juan Cruz Mallia, Jeronimo De La Fuente, Santiago Carreras; Nicolas Sanchez, Felipe Ezcurra; Nahuel Tetaz Chaparro, Julian Montoya, Santiago Medrano, Guido Petti Pagadizaval, Matias Alemanno, Pablo Matera, Juan Manuel Leguizamon, Rodrigo Bruni.

Replacements: Agustin Creevy, Mayco Vivas, Enrique Pieretto Heiland, Marcos Kremer, Tomas Lezana, Gonzalo Bertranou, Benjamin Urdapilleta, Matias Moroni.

USA: Mike Te'o, Blaine Scully, Bryce Campbell, Paul Lasike, Marcel Brache; AJ MacGinty, Ruben De Haas; 1-Eric Fry, Joe Taufete'e, Titi Lamositele, Nate Brakeley, Greg Peterson, Tony Lamborn, Hanco Germishuys, Cam Dolan.

Replacements: Dylan Fawsitt, Olive Kilifi, Paul Mullen, Ben Landry, Ben Pinkelman, Nate Augspurger, Will Hooley, Martin Iosefo.