Two second-half penalties from Morné Steyn saw South Africa come from behind to win 22-17 in a brutal match against Argentina.
The Springboks were unable to produce the same clinical finishing that saw them rack up so many point last weekend, sucked into a breakdown battle that they often lost until Steyn's boot prevailed in the closing stages.
Argentina, as widely expected, were completely unrecognisable from the sham that turned up at Soccer City last weekend and conceded nine tries.
A repeat of last weekend's 73-13 hammering in Soweto was always unlikely, with Argentina far more productive at containing the Springboks at the breakdown and in the set-pieces.
The hosts general attitude though was outstanding, taking the game to a South Africa side whose execution was far from the excellent level produced the week before.
Mendoza was the setting for the 18-18 draw between these two sides last season and once more South Africa looked unsettled early on.
The hosts couldn't have wished for a better start. Capitalising on loose ball at the ruck, Argentina surged upfield and from an attacking lineout five metres out they unleashed a clever rolling maul, with Juan Manuel Leguizamon touching down despite a hint of obstruction inside the opening three minutes.
Steyn and Felipe Contepomi traded penalties before the Springboks drew level, Bjorn Basson finding his way over after a harried turnover at the ruck created an overlap on the left-hand side.
It was a score that perhaps would have eluded a maturing South Africa side a year ago, but the 2013 version is a different beast and made the most of this rare chance.
Juandré Kruger's try was ruled out for an earlier knock-on at the lineout closely after Ruan Pienaar was also denied a score, beaten to the bounce in the dead-ball area by Martin Landajo.
South Africa were struggling to find the fluidity that served them so well a week before and their attitude was puzzling; a poor decision to opt for the corner instead of a simple penalty backfired on the Boks as an easy three points went begging with 25 minutes gone.
Their attack was also littered with knock-ons, with every single one giving the home side and their supporters renewed hope.
That hope was then converted into a second try; centre Marcelo Bosch forcing his way over through the tackle of Jannie du Plessis to put the Pumas up 17-10, Steyn responding with a long-range penalty before half-time.
Fired up by a rollicking from Heyneke Meyer, the Springboks were reinvigorated after the break and another Steyn penalty cut the deficit to just one point.
The penalty count began to creep up on the Pumas as the second half wore on, who showed at times too much enthusiasm at the breakdown.
Contepomi's departure with a shoulder injury felt like hammerblow to Argentina's prospects, but the continued tenacity shown by the hosts at the ruck meant that they kept their slender lead.
Repetitive small errors didn't help to calm what was already a tempestuous atmosphere and young lock Eben Etzebeth was penalised for lashing out, due to his unhappiness over a reported bite from an Argentinian player.
Experience was introduced in the form of Bismarck du Plessis, who won his 50th cap off the bench and capped it with a series of effective choke tackles to stifle Argentina's possession — but the Boks were still facing an uphill battle.
Steyn's penalty in the 71st minute after a collapsed maul finally put South Africa ahead for the first time in the match — a slender two-point lead silencing the crowd as the match drew to a close.
Desperate to create a final opportunity, Argentina failed to produce the necessary field position to generate a penalty or drop goal, instead finding themselves pinned back in their own 22.
Steyn's final penalty confirmed the result, but Argentina should take heart from an encouraging performance, despite their first win in The Rugby Championship still eluding them against an average South African performance.
The scorers:
For Argentina:
Tries: Leguizamon, Bosch
Cons: Contepomi 2
Pen: Contepomi
For South Africa:
Try: Basson
Con: Steyn
Pens: Steyn 5
Argentina: 15 Lucas Gonzalez Amorosino, 14 Gonzalo Camacho, 13 Marcelo Bosch, 12 Felipe Contepomi (captain), 11 Horacio Agulla, 10 Nicolís Sínchez, 9 Martín Landajo, 8 Leonardo Senatore, 7 Juan Manuel Leguizamí³n, 6 Pablo Matera, 5 Mariano Galarza, 4 Julio Farías Cabello, 3 Juan Figallo, 2 Eusebio Guiñazú,1 Marcos Ayerza.
Replacements: 16 Agustín Creevy, 17 Nahuel Lobo, 18 Tomas Lavaninni, 19 Benjamin Macome, 20 Tomís Cubelli, 21 Santiago Ferníndez, 22 Joaquin Tuculet.
South Africa: 15 Willie le Roux, 14 Bjorn Basson, 13 JJ Engelbrecht, 12 Jean de Villiers (c), 11 Bryan Habana, 10 Morné Steyn, 9 Ruan Pienaar, 8 Duane Vermeulen, 7 Willem Alberts, 6 Francois Louw, 5 Juandré Kruger, 4 Eben Etzebeth, 3 Jannie du Plessis, 2 Adriaan Strauss, 1 Tendai Mtawarira.
Replacements: 16 Bismarck du Plessis, 17 Gurthrí¶ Steenkamp, 18 Coenie Oosthuizen, 19 Flip Van Der Merwe, 20 Siya Kolisi, 21 Jano Vermaak, 22 Pat Lambie, 23 Jan Serfontein.
Date: Saturday, August 24
Venue: Estadio Malvinas Argentinas, Mendoza
Kick-off: 16.10 (19.10 GMT)
Referee: Steve Walsh (Australia)
Assistant referees:John Lacey (Ireland), Pascal Gauzí¨re (France)
TMO: Marshall Kilgore (Ireland)
The result means Heyneke Meyer's team claim the silverware at the end of the four-nation quadrangular series involving Italy and Scotland, but more importantly, they bounced back from an under-whelming display in Nelspruit a week ago.
The result leaves Italy win-less on their three-game tour of South Africa having already lost to Samoa and the Springboks.
The Pacific islanders scored four tries against the Americans' one during the game in Nagoya, central Japan.
The loss is Canada's first in the 2013 competition and means that either Fiji or Tonga, who face each other on Sunday, June 23, can win the title.
Tonga, who fell 36-27 in Ontario last Saturday to unbeaten Canada, were without three players suspended by the IRB as a result of last week's match — full-back David Halaifonua, prop Eddie 'Aholelei and centre Siale Piutau.
Canada came into the contest riding high, after victories over Tonga, Fiji, the United States and Russia.
It was a success built on the solid foundations of a dominant scrum that created fourteen points through two penalty tries during the first-half.
Scotland have never won on South African soil and with an under-strength side, few expected the tourists to trouble the Boks on their first visit to Mbombela Stadium. But it turned out to be a tightly-contested affair and the hosts looked in trouble when they trailed by 11 points early in the second half and only led by three with six minutes left to play.
The Italian scrum was their only source of a joy in a dire performance, with Samoa holding firm in defence and also excelling in open play by racking up several long-range tries.
The hosts' win — their first ever triumph over Wales — is sweet revenge after they suffered a narrow 22-18 loss to their opponents in Osaka last Saturday and secures them a 1-1 draw in the series.
Stuart Lancaster's side stormed out of the blocks in the opening 40 minutes to rack up tries through David Strettle, Billy Twelvetress and Ben Morgan — the latter pair particularly impressive throughout on their return to Test rugby.
The USA proved to be stubborn opposition in Houston as they kept the scoreline close throughout.