Dragons RFC scrum half Gonzalo Bertranou started as Argentina kept their quarter-final hopes alive with a hard-earned 19-10 victory over Samoa in Saint-Etienne in Pool D.
The Pumas recovered from their opening game defeat by England to kickstart their campaign at a rain-drenched Stade Geoffroy-Guichard.
Argentina wing Emiliano Boffelli converted his own try and kicked three penalties to finish with 16 points.
Sama Malolo powered over late on to set up a frantic finish but Nicolas Sanchez's penalty sealed victory.
The Pumas are next in action when they face Chile on Saturday (September 30).