Argentina fought back from a 14-0 deficit to edge Australia 21-17 in Mendoza and seal their maiden victory in the Rugby Championship.
Both sides scored two tries apiece with the difference coming from the boot of Pumas flyhalf Nicolas Sanchez as Argentina won a controversy-tinged contest in the southern hemisphere tournament at the 18th attempt.
With the visitors trailing 18-17 with 10 minutes to spare, Wallabies flyhalf Bernard Foley had a chance to pull his team in front with a penalty kick from close range but he hit the post after having a laser trained on his face from the crowd.
Minutes later, a harsh yellow card saw Wallabies captain Michael Hooper sin-binned for a dangerous challenge on Sanchez and the flyhalf duly made sure of the win with a penalty goal five minutes from time.
The win in the final round of the tournament was Argentina's first over Australia since 1997 and their fifth over the Wallabies in 23 meetings.
Hooper's yellow card was the third of three handed out to the Wallabies in the second half, with scrumhalf Nick Phipps spending time in the bin shortly after the break.
Referee Nigel Owens later over-ruled his own decision to send off fullback Israel Folau for tackling a player in flight after reviewing a video replay.
Argentina had the lion's share of territory and possession in the first half yet found themselves 14-0 down after 13 minutes after tries by centre Tevita Kuridrani and number eight Scott Higginbotham.
The Pumas pushed the Wallabies back deep into their half but they had to wait until the 35th minute for their reward when they finally edged past some impressive defence with a try by number eight Leonardo Senatore.
Sanchez failed with the conversion but slotted his first point from a penalty on the stroke of halftime to narrow Australia's lead to 14-8 at the interval.
Argentina gained a numerical advantage early in the second half when Phipps was sent off for a scrum infringement and Sanchez slotted his second penalty to edge the Pumas closer.
However, the flyhalf knocked on minutes later deep in Pumas territory and though Australia were denied a possible try in the right corner after a lengthy video review, Foley converted the penalty to give his side a six-point buffer.
That was erased when winger Juan Imhoff crossed over for the Pumas' second try and Sanchez's conversion put the hosts ahead for the first time in the 53rd minute.
The match became attritional as the tiring Wallabies doggedly tried to fend off Argentina's charge but the tourists' resolve buckled after the loss of Hooper and Sanchez coolly sealed the win to end three years of frustration for the Pumas.
