Buenos Aires (Argentina) (AFP) - World champions South Africa withstood a 15-phase post-hooter attack to edge Argentina 17-10 in a tense one-off Test in Buenos Aires on Saturday and stretch a winning streak to 12 internationals.

Pumas substitute wing Matias Moroni sobbed as the final whistle blew after he knocked on a pass with the tryline at his mercy.

After poor recent form by Argentina, losing at home to Scotland and England in the Nations Championship, they showed vast improvement against the record four-time world champions.

South Africa captain and flanker Siya Kolisi, whose return from injury lasted only 25 minutes before limping off, said the Test turned out as he expected.

“It was a tough game. A lot of our players are coming back from injuries. We did not execute well in the first half,” he told reporters.

“The Pumas are a great team and are passionate, just like us. This is why we like coming here. We are looking forward to the coming All Blacks series and this was a great preparation.

“I hurt my hamstring again so I will have to go for a scan. It is really tough,” he added, with the first Test against arch rivals New Zealand on August 22.

Displaying commitment and physicality, the Pumas led 10-3 for most of the first half at a packed Estadio Jose Amalfitani, which ended with the teams level at 10 points each.

The Springboks dominated the second half, but 63 minutes had elapsed before the vital breakthrough came from outstanding No. 8 Cameron Hanekom.

South Africa won a scrum five metres from the Argentine tryline and Hanekom barged over for a try that Handre Pollard converted.

A nervous finish for South Africa saw Argentina force a 50-22 line-out, then a tap-and-go penalty, which ended sadly for Moroni.

Argentina, lacking unavailable captain and hooker Julian Montoya and suspended fly-half Tomas Albornoz, went ahead on three minutes when playmaker Santiago Carreras slotted a penalty.

Fly-half Sacha Feinberg-Mngomezulu, one of several Springboks making their first appearances of the season after injuries, levelled soon after from a close-range penalty.

Flanker Benjamin Grondona then received the ball after a maul, powered his way to the tryline and Carreras converted.

The world champions levelled on the stroke of half-time when wing Edwill van der Merwe showed superb pace to dart along the touchline then touch down between the posts.

Feinberg-Mngomezulu converted and South Africa left the field for the break relieved to be level after failing to sparkle in a scrappy first half.

Carreras struck the post from a second-half penalty, then Andre Esterhuizen was held up over the tryline before Hanekom struck.

Both sides were preparing for home series. South Africa play four Tests against New Zealand and Argentina two against Australia.