The 'Ikale Tahi are all but out of playoff contention after a 28-12 defeat by the Pumas in Higashiosaka left then winless and without a point after two games.
Argentine hooker Julian Montoya bagged a hat-trick inside 25 minutes as the South Americans raced out to a 28-0 lead.
The 'Ikale Tahi were given a lifeline just before the half-hour mark when fullback Telusa Veainu weaved past two defenders to score their first try of the tournament.
