'Exciting young prospect': The Wallabies youngster set to cause the All Blacks 'damage'

All Blacks playmaker Richie Mo'unga believes Wallabies rookie Noah Lolesio wouldn't want it any other way than to be thrown in the cauldron of a Bledisloe Cup test in Sydney on Saturday.

Aged just 20, Lolesio will make his test debut at five-eighth in the must-win match following injuries to both James O'Connor and Matt Toomua.

But Mo'unga believes that after steering his Brumbies outfit to the Super Rugby AU title, Lolesio is up for the challenge.

"It's tough just being thrown in there but I don't think Noah would have wanted it any other way than starting a test match in Australia against the All Blacks," Mo'unga said.

"For him, that's the perfect outcome and that's what he wants and he's being rewarded for the season that he's had."

"He's an exciting young prospect and he'll embrace it."

Mo'unga, 26, said he had enjoyed watching Lolesio this season from across the Tasman, and would be keeping much closer tabs on him on Saturday night with so much at stake.

A victory by the All Blacks would see the Bledisloe Cup remain in their grasp for an 18th year.

He expected Wallabies coach Dave Rennie would give the youngster freedom to play his own game rather than try to fit the mould of O'Connor.

"I think he can do some damage out on the field so he's a player we definitely need to keep an eye on.

"I assume they're just going to tell him to be himself; it's no point throwing someone who is young in there and expecting him to play like O'Connor.

"They're going to back his skill-set, back his strengths and him to get some good touches early on which will help his game and help Australia."

Playing his 20th test, Mo'unga knows a thing or two about pressure - and not just from the opposition.

With only a 60 per cent win rate starting at five-eighth against top-tier opposition, he still faces question marks over his selection ahead of Beauden Barrett, who will play at fullback.

Mo'unga said he didn't read the criticism and felt he judged himself more harshly than others.

"The pressure of playing No.10 is really tough, and the pressure I put on myself is a lot more than what the external pressure is," he said.

"I have tools in place, you know, to help me get through that.

"For me it is not about worrying what other people think, apart from myself and what my brothers thinks left and right of me."