The Jaguares downed the Brumbies 20-15 in a bruising Super Rugby encounter in Buenos Aires on Saturday.
It was a controversial win for Argentine hosts Jaguares, whose try prior to half-time was awarded by TMO for a 17-15 lead.
Matias Orlando appeared to be tackled by Pete Samu but the Jaguares centre kept heading to the try line to score.
The try went upstairs and it was ruled in favour of the Jaguares, who opened the scoring via Sebastian Cancelliere in the third minute.
Folau Fainga'a responded for the Brumbies as he crossed over for his seventh try of the season before team-mate Matt Lucas set up Tom Banks for the five-pointer.
Following Orlando's controversial try, a 61st-minute penalty saw the Jaguares extend their lead and despite Marcos Kremer's yellow card, Australian visitors the Brumbies were unable to capitalise.