Argentina captain Agustin Pichot has tipped Australia to grow in confidence during the World Cup and would not be surprised to see the host nation claim their third world crown.

Eddie Jones' side looked uncovincing in Friday's 24-8 opening game triumph over the Pumas but former Bristol scrum-half Pichot expects Australia to improve as the competition progresses.

"With home advantage, they will gain momentum as the tournament goes on and they should go very close," said the 30-year-old.

"They went into last night's game under a lot of pressure, with quite a few people writing them off. I wasn't one of them because they are still one of the best sides in the world.

"We didn't play to our potential but you have to give them credit for that.

"Australia did their homework very well and though they didn't play good rugby, it was very effective.

"They neutralised us close to the rucks, put pressure on our set piece and generally disrupted us in the areas where we are usually on top. They will gain a lot of confidence from this win."

Pichot may well have a new half-back partner when Argentina resume their campaign with a must-win clash against outsiders Namibia in Gosford on Tuesday.

The gamble of playing Felipe Contepomi at stand-off in preference to Gonzalo Quesada failed miserably. Contepomi failed with four of his five shots at goal, plus a attempted drop-goal, errors which proved crucial in the final outcome.

Former Northampton hooker Federico Mendez might also hope for a start having watched Mario Ledesma suffer a nightmare with his line-out throwing.

Ledesma was penalised five times by referee Paul Honiss for failing to produce a straight throw, although coach Marcello Loffreda refused to condemn the Kiwi official.

"We will have to work on some things to do with the referee's interpretation of the match because it cost us some vital field position," he said.

"But I haven't any complaints about Honiss. I thought he did quite well.

"As for the goalkicking, it was not a good night but Felipe has done well for us in the past before so there was no reason to suggest he couldn't do the same last night."