Pumas skipper Agustin Pichot says his side felt fatigued during its hard-fought quarter-final win over Scotland in Paris on Sunday.

The Pumas had come out on top of its Pool following some hugely demanding matches against France, Scotland and Georgia including two matches in five days at the start of the tournament.

"We were very tired and Scotland played very well. But we stuck with it," Pichot said after the match.

"Scotland were very good and we didn't underestimate them.

"They have a great team and we have a lot of respect for them."

Argentina now faces a tough semifinal against South Africa.

Meanwhile, Scotland flanker Allister Hogg believed his side wasted a few opportunities to win the match in the dying stages.

Replacement halfback Chris Cusiter scored a try for Scotland but despite some late pressure his side was unable to capitalise when a converted try would have won the match.

"We had some chances today and felt we had the beating of Argentina and could go further in this tournament, so we're disappointed," Hogg said.

"It was pretty tough. We tried to play a bit of a territorial game but it didn't come off.

"They are a good side, well drilled, they know each other very well and play together well.