Wallabies coach Les Kiss lamented Saturday his side letting Argentina "off the hook" as his four-match win streak came to an end with Australia failing to exploit a late two-man advantage in a 28-28 draw.
Since Kiss took the reins from Joe Schmidt, Australia secured a 27-21 victory last week against the Pumas and had two successes against Japan before failing to capitalise on 14-0 lead in Mendoza.
Even so, the result gave the Wallabies a 1-0 series win, their first in Argentina.
"It's difficult to come here and do what we did. But we let them off the hook a couple of times," said Kiss.
"We were up two tries to nil in that first half, and just gave them field position, gave them opportunity, and that brought the crowd back in, that brought the energy back into their game.
An arm wrestle in Mendoza.
— Wallabies (@wallabies) September 5, 2026
Always a tough contest, @lospumas 🤝 pic.twitter.com/XLdFZFpJZB
"It was always going to become a dogfight from there on in," he added.
"But the boys had a lot of defence to do in their own line, and I thought there was some really good stuff that came from that area.
"A series win, a trophy. There's some good stuff in there as well. But we know we have things to work on."
It was a bruising affair, dominated by eager forwards, with Australian playmaker Carter Gordon a key casualty, limping off late in the second-half.
Argentina did at least halt a run of three straight defeats, although they remain on just the single victory in this calendar year, against Wales in July.
Australia opened the scoring halfway through the first half courtesy of captain Harry Wilson in a move stemming from a lineout.
After Pumas lock Franco Molina was sent to the bin, wing Max Jorgensen extended the Wallabies' advantage.
The game then turned on a yellow card for Australia lock Jeremy Williams, with Argentina responding through captain Pablo Matera despite being a man down themselves.
Back to full strength, the hosts levelled things up after Ignacio Mendy burst through a gap to score as the teams went into the sheds at 14-14.
The forward battle continued after the break as flanker Fraser McReight restored Australia's lead, only for hooker Ignazio Ruiz to level up again.
Flanker Matera barged over for his second after Argentina went through 23 phases against a desperate defence.
The Pumas then imploded, receiving two yellow cards in quick succession for deliberate knock-ons by their two most experienced backs.
Lucio Cinti went first and fly-half Santiago Carreras followed, giving away a penalty try in the process to level the scores at 28-28.
Despite playing the last 10 minutes with a significant advantage, Australia did not come close to snatching a winning score.
"We put ourselves in the position to win ... we're hurting, we really wanted to win that." said Wilson.
"But to bring back the trophy's great ... it brings some momentum and confidence into the group."