Samoa A has handed two-time defending Americas Pacific Challenge champions Argentina their first loss in the three-year history of the tournament, beating 36-31 on Sunday.
In what was a good opening day for the Oceania representatives, Tonga A also recorded a 39-30 victory against last year's runners-up, the USA Select XV, while Uruguay A christened the new artificial pitch at their Estadio Charrua home with a 35-21 win against their Canadian counterparts.
In sunny conditions at the Estadio Cahrrua in Montevideo, Argentina XV finally lost their unbeaten record at the Americas Pacific Challenge.
Argentina XV had won all six of their previous matches at the key development tournament, including an 85-14 win over Samoa A 12 months ago, but they were well beaten here with the final scoreline not doing the Pacific Islanders justice.
Determined to put the record straight from last year, Samoa A got off to a storming start and, by the 20th minute, had already scored two tries. Miakele Tapili was the first to cross, the second-rower running down the right touchline and breaking through some feeble tackles before full-back Johnny Vaili collected a chip kick that caused mass confusion in the Argentinian ranks for the second.
Patrick Faapale's conversion was followed by two penalties from the boot of centre Alai Leuila as Samoa A raced into an 18-0 lead.
Argentina XV were given an invaluable lifeline when loose-head Rodney Tapu was sent to the sin-bin in the 23rd minute, the defending champions capitalising on their numerical advantage to score through full-back Bautista Daireaux. Winger Leopoldo Herrera added a second shortly after the Samoans were restored to their full complement of players and with Joaquin Bonilla converting both, the gap between the sides was down to just four points.
The second half was similar to the first, with Samoa playing the better rugby and adding points through Leuila's third penalty and a try from wing Johnny Samuelu who showed his aerial ability in claiming a high ball.
Argentina XV replied after another Leuila penalty, replacement hooker Axel Zapata touching down in the 65th-minute to bring the score back to 29-19 to the Islanders.
Six minutes later, Samoa A flanker Petelo Mapu made the game safe when he bumped off a tackle to finish from 15 metres, Leuila converting to take his points tally to 14 for the match.
Santiago Carreras and Santiago Portillo scored late tries as the Argentinians secured two bonus points.