The Pumas say they're ready for the "battle of South America" against Chile after getting off the mark in the World Cup by beating Samoa on Friday.
Right wing Emiliano Boffelli starred for Argentina, scoring their only try and contributing 16 points in the 19-10 success against the Pacific Islanders.
It was a crucial victory after the Pumas lost their Pool D opener 27-10 to England two weeks ago.
Next up will be Chile in the first ever Rugby World Cup clash between two South American nations.
"The next game is very important for many reasons because we know Chile will give everything to attack us," said head coach Michael Cheika. "It's logical, it's the battle of South America and we have to be ready. That's good for us because every World Cup match is a war, we have to be ready for all of them."
Cheika said the Pumas had made progress since the listless defeat to 14-man England, but he expects more to come.
"The defensive foundations were there, the maul was much better than the previous match," he said. "The basics were there, territorial (occupation) was there, but we need to be more clinical in moments. But a lot of respect to the players, this was a die-or-survive match and I was happy to always be in the game."
After Chile, Argentina will play Japan in what may be the decisive match to see who progress to the quarter-finals.
Disciplined and composed
Boffelli scored 16 points as the Pumas got their World Cup campaign back on track with a disciplined and composed victory/
"We knew it wouldn't be easy. Samoa are a strong team. It was a very important win today," Boffelli said. "The supporters were incredible. We felt their support."
An error-strewn display proved Samoa's undoing, with numerous knock-ons halting their progress and momentum.
Samoa did set up a grandstand finish when replacement hooker Sama Malolo burrowed over five minutes from time, before Argentina veteran Nicolás Sánchez ended Samoan hopes with a last-gasp penalty.
"Extremely proud of the boys today," said Samoa captain Chris Vui. "I thought the better team won, all credit to Argentina, they were more clinical, so full credit to them."
Samoa made a poor start and then paid for some hapless kicking and dubious tactical choices as Argentina steadily clocked up the scores in driving rain.
Samoa full-back Duncan Paia'aua was yellow-carded inside the first 35 seconds for taking out Santiago Carreras in the air.
Just before Paia'aua returned, Argentina made Samoa pay, switching play from one wing to the other before Boffelli darted in off his flank to stretch out an arm and score.
Samoa had been the architects of their own downfall, as veteran fly-half Christian Leali'ifano gifted Argentina possession inside the 22 by taking a free-kick from the wrong place.
Boffelli converted his own try and soon added a penalty before Leali'ifano got the Pacific Islanders off the mark with a three-pointer that bounced on the crossbar and over.
A second penalty from Boffelli pushed Argentina's lead to 13-3, while Leali'ifano missed two straightforward looking kicks at goal in what was quickly turning into a personal horror show.
Leali'ifano turned down another penalty opportunity to kick to the corner but Argentina stole the Samoan line-out.
Moments later, on the stroke of half-time, Samoa had a five-metre scrum, but scrum-half Jonathan Taumateine spilled the ball and allowed Argentina to survive and take a 10-point lead into the break.
With the rain abating, Argentina grew in confidence at the start of the second half, pinning Samoa in the corner before giving away a penalty from a double movement by Boffelli as he sought a second try.
Samoa lost UJ Seuteni, knocked out while making a tackle, and another botched line-out invited more pressure.
A clever Pablo Matera grubber kick led to a penalty deep in the Samoa 22 that Argentina kicked to the corner.
Fierce defence kept Argentina out until Boffelli knocked over his third successful penalty.
Boffelli missed a penalty from halfway, but made up for that with some crucial cover under his own posts to prevent Tumua Manu from running onto a grubber to score.
Samoa finally scored a try five minutes from time through Malolo, with D'Angelo Leuila converting.