Argentina face a nervous wait to find out the extent of Juan Martin Fernandez Lobbe's knee injury.

The star number eight will undergo a scan on Monday morning after limping out of Argentina's dramatic 13-12 win against Scotland that kept their Rugby World Cup dreams alive.

"It's not looking good," admitted the Toulon player immediately after the match at Wellington Regional Stadium.

Fernandez Lobbe was also joined on the sidelines in the first half by prop Rodrigo Roncero who hurt himself in a scrum.

Coach Santiago Phelan said he would also be assessed further.

"He pulled a muscle. We just need to find out the full extent of the injury," he said.

Lucas Gonzalez Amorosino and veteran Felipe Contepomi were the heroes for the Pumas.

Trailing 12-6 with seven minutes to go, Amorosino danced past three defenders to score a superb solo try, which Contepomi converted to put Argentina in front for the first time since the 18th minute of the match.

"It was an important game for the team. It was a must-win game," Contepomi said.

"Maybe we didn't manage to play the way we practiced. But it's very important that we managed to turn around six points in the final 10 minutes."

Contepomi, playing at his fourth World Cup, is used to playing in pressure situations but admitted when they were six points behind in the wet and blustery conditions that he was not sure where the try they needed was going to come from.

"But then when Luca scored I came to him and said 'what a great try but now I have to convert it'," he joked.

Having missed three of his five penalty attempts it would have been understandable had Contepomi been nervous about the conversion.

"You come back to what you do," he explained. "You just focus on every single ball. It's a tough pitch to kick because the wind is a bit all over the place. But I had confidence in all my practice and just tried to do it the best way and this time it went through, sometimes it doesn't."

Scotland coach Andy Robinson said it had been '30 seconds of madness' that had cost his side, who he believed had outplayed the Pumas for much of the match.

Contepomi, who played with sore ribs, did not disagree.

"They played probably better than us but rugby is 80 minutes. Us against England I think we had 30 seconds where we lost the plot and we let them score," he said.

"Unfortunately maybe we played better than them that day but we lost. So this time the ball bounced to our side."

Argentina play Georgia next Sunday. With Scotland needing to beat England and prevent them from gaining a bonus point, the Pumas have their destiny in their own hands now.

"It's a great plus for us that we now depend on ourselves," said Contepomi. "We have one more game to play against Georgia and look forward to that to try and qualify."

"We haven't achieved anything yet. Now we are in the driving seat in playing Georgia and trying to get qualification. That's what we're here for."