Late try gives All Blacks a bonus-point win
Ben Smith of New Zealand runs the ball forward during a match between the New Zealand All Blacks and Argentina on September 7, 2013
The result moves the All Blacks five points clear of South Africa at the top of the table ahead of their showdown at Ellis Park in Johannesburg next weekend.
Right-wing Smith struck for the second time in the match with just 27 seconds left, using brain and brawn to dive over beside the posts.
New Zealand triumphed 54-15 at Estadio Ciudad de La Plata last season, but it was a much closer contest this time with handling errors costing Argentina dearly at times.
Argentina had an early chance to take the lead from a long-range penalty, but centre Marcelo Bosch saw his attempt drift well left of the posts.
Los Pumas switched goal-kickers for a shorter shot soon after and fly-half Nicolas Sanchez made no mistake to nudge the home side ahead.
All Blacks playmaker Aaron Cruden, starting in place of injured Dan Carter, levelled from another penalty four minutes later.
Sanchez restored the Pumas' advantage with another successful penalty and missed a further attempt, leaving Argentina 6-3 ahead midway through the opening half.
But once again the lead was short-lived as left-wing Julian Savea snapped up a loose ball in midfield and darted down the wing to go over in the corner.
Cruden was off target with the conversion only to be given a second chance because a spectator shone a green laser at him.
The playmaker appeared unsettled by the incident and missed his second chance as well with the ball again veering left of the near post.
Cruden did succeed with a penalty shot and so did Sanchez, giving the 2011 Rugby World Cup winners an 11-9 lead at the break.
That changed to a one-point deficit four minutes into the second half as Bosch comfortably slotted his second 50-metre effort between the posts
However, the All Blacks were never prepared to trail for long and just two minutes later Cruden kicked his third penalty of the game to restore a two-point lead.
New Zealand were looking increasingly dangerous on attack and flank Sam Cane and Smith crossed the try-line within five minutes to push the visitors 26-12 ahead.
Cane dived over in the corner after slick handling took the ball from one side of the field to the other, but Cruden fluffed the conversion.
Smith claimed his sixth try of the Championship this season by bursting through the middle after being set up by a moment of magic from veteran centre Ma'a Nonu.
Cruden converted this time before the rattled Argentines regained some composure and Sanchez kicked his fourth penalty of the game.
With 10 minutes left it was 26-15 to the All Blacks, and they needed one more try for a bonus point and a five-point advantage over great rivals the Springboks.
It appeared to have eluded the visitors until Smith ran through and South Africa must win with a bonus point and prevent New Zealand gaining any points to snatch the title.