Former Wallabies captain John Eales says Australia must build on confidence gained from their scrappy win over Argentina to make an impact at this year’s Rugby World Cup.

The Wallabies clinched the much-needed 16-10 victory on Saturday in Brisbane for just their fourth win in 14 Tests but, with consecutive Rugby Championship showdowns with world champions New Zealand looming, Michael Cheika’s side need to improve quickly.

Eales, a two-time world champion in 1991 and 1999, believes this squad need to trust in their abilities if they are to be successful when the World Cup begins on September 20 in Japan.

“I think there is talent there but I think what they need to work on is a true belief in themselves,” Eales said on Monday in Tokyo.

“I think they think they can win the big games but it is about getting that consistency in performance that they start to win the big games more often than not.

“There is potential there.”

On Saturday, Argentina’s Facundo Isa scored a try with six minutes remaining, but Australia’s defence held firm and this tenacity impressed Eales the most.

“I think one of the most important things we saw in that game was the ability for the team to produce across 80 minutes,” said the 49-year-old, who captained Australia in 1999.

“Yes, there were some mistakes and they could have scored more tries but, when the game was in the crux moments at the end, they actually took some control of that game.

“The team didn’t panic, they maintained their calm and stayed composed.”

Australia have reached the semi-finals at every World Cup, bar two, including their 2015 final loss to the All Blacks.

Eales believes this is why the Wallabies shouldn’t be ruled out, despite their poor form, and backs coach Cheika’s team to build momentum during the tournament.

“The way you perform and go through a tournament is quite different because really the only thing that matters is the next game,” said Eales.

“Whatever you did that week, if it got you through, then it doesn’t matter.

“It is just about keeping on progressing and you will have those moments of luck, chance or magic.”

Australia begin their bid for a third World Cup on September 21 against Fiji in Sapporo. Also in Pool D are Wales, Georgia and Uruguay.