Lambie will start his fourth game of the tournament in the No 15 jumper on Sunday and is an important figure in the squad since the departure of utility Frans Steyn, who was sent home with a shoulder injury this week.
The final-eight clash will be only Lambie's 11th test, but Habana said the 20-year-old continued to impress him.
"I think having seen Pat's growth back home in South Africa over the last two years, he's a 20-year-old that's got an unbelievable head on his shoulders for such a young guy,'' Habana said.
"So, no [I have] a lot of faith in his ability. He's not only a great rugby player but he's also a fantastic person off the field as well. I think John Smit said it probably the most correctly in that I think he's the only rugby player that he'll let his daughter go out with. That's the type of guy he is and his attitude off the field really speaks for what he is on the field and like I say he's sort of growing in his stature as a fullback.''
Habana, Lambie and JP Pietersen make up South Africa's back three who will be charged with fielding kicks from the boots of Quade Cooper and Kurtley Beale in the swirling wind of Wellington Regional Stadium.
Habana's endorsement of Lambie may be one thing, but the rookie is a break in the mould from the rest of the team.
While he still looks young enough to be asked for identification to buy a dozen of beers, the rest of the Springboks outfit is filled with veterans loaded with the battle scars of experience on the international stage.
Even the 25-year-old Pietersen has racked up 41 test-match appearances, while a bulk of the squad played in their 2007 World Cup triumph.
Despite his lack of international experience, Habana said Lambie brought plenty of enthusiasm to the team environment.
"Speaking to someone like Patrick Lambie and seeing his energy and his excitement after having played in Super Rugby quarter-finals, Currie Cup finals and semifinals back home. I think he's just as excited and I think that energy and that excitement together with the experience and leadership of guys like John, Victor [Matfield], Fourie [du Preez], Schalk [Burger] and guys from 2007 that have been there makes it a really fantastic mix of emotions.''
Australia have won five of their last six clashes with the Springboks and Habana said the inside back pairing of Will Genia and Cooper had begun to flourish.
"You look at the halfback pairing [of Genia and Cooper] that's been with the Reds over the last couple of years. They've been together since they were 17-years-old. I think their youngsters have really put their hands up. Their more experienced guys have given them a great foundation and they've gone out and every encounter has always been tough against us and they showed that in the last six.''
Then again, despite their woeful recent record, Habana, the Springboks' all-time leading try scorer, said those past clashes counted for little this weekend.
"They've got an advantage over us at the moment. But in a knockout game, that means nothing. It's a do-or-die game for 80 minutes and we've both got an opportunity to progress. So I think history won't count too much.''
South Africa will be without veteran lock Bakkies Botha for the match, who was ruled out of the tournament yesterday with an Achilles injury with Danie Rossouw set to start alongside Matfield in the second row.