Replacement fly-half Santiago Gonzalez Iglesias kicked a penalty two minutes from time to give Argentina a 26-24 Rugby Championship victory over South Africa in Salta Saturday.
It was the first home triumph for the Pumas over the Springboks after a draw and 10 defeats since they first met in South America 23 years ago.
The lead changed several times before Iglesias, the third-choice goal-kicker after fly-half Nicolas Sanchez and centre Juan Martin Hernandez retired injured, slotted the match-deciding kick.
"Argentina were very good while we made a lot of errors," said Springboks skipper and hooker Adriaan Strauss.
"We need to take a long, hard look at ourselves and fix what has gone wrong before playing in Australia and New Zealand next month."
South Africa fly-half Elton Jantjies went into the match under a cloud after a series of indifferent performances and he fluffed an early chance to score from a penalty, which drifted right.
Giant Argentina winger Manuel Montero crossed the try-line on 17 minutes only for a television match official review to expose that he knocked on.
The hosts were temporarily reduced to 14 men when tighthead prop Ramiro Herrera made a late, no-arms tackle on flanker Francois Louw and was sin-binned.
Jantjies opened the scoring on 21 minutes, succeeding with his second penalty kick amid sustained whistling from the partisan crowd.
But the lead lasted just two minutes as Sanchez scored off his first penalty opportunity at Estadio Padre Ernesto Martearena.
Centre Matias Orlando was bundled into touch just short of the try-line and a home side making light of being a man down went ahead when Sanchez goalled another penalty.
Herrera returned from his 10-minute spell on the touchline and almost immediately Argentina scored a brilliant try.
Breaking on the blindside from midfield, the ball went through numerous Argentine hands before Montero sent full-back Joaquin Tuculet over the try-line.
Sanchez converted to maintain his perfect goal-kicking record and Jantjies missed another penalty, leaving Argentina 13-3 ahead at half-time.
However, it took twice former world champions South Africa just six minutes of the second half to notch 10 ponts and draw level.
Jantjies slotted a penalty and a clever backward off-load from Louw sent veteran winger Bryan Habana racing clear to dot down and full-back Johan Goosen converted.
Sanchez was injured in the build-up to the try and left the field with blood on his face to be replaced by Iglesias.
South Africa took off unimpressive Jantjies and introduced veteran France-based playmaker Morne Steyn.
Argentina quickly regained the initiative with flanker Juan Manuel Lequizamon scoring a try in the corner after outjumping Habana to a cross kick from Hernandez.
In the absence of Sanchez, Hernandez took over the goal-kicking duties and followed up a successful conversion with a penalty to restore the 10-point advantage they had at the break.
Steyn penalties either side of a try from replacement lock Pieter-Steph du Toit nudged the Springboks to a 24-23 lead before Iglesias struck.