He's locked up the No 10 jersey ahead of Beauden Barrett, who's found his home as starting fullback.
The pair were used as dual playmakers at the 2019 World Cup, where the All Blacks were beaten in the semi-finals, and Mo'unga says having clearly defined roles has improved their performances in 2023.
"This is the first year in many years that we haven't had the issue or the debate around who's going to be playing what. It's nice to have that peace of mind.
"In 2019 we just wanted to do whatever was best for the team and it's exactly the same this year. It's just nice for both of us having clarity around our roles. For Baz (Barrett) too, he's just getting his role at 15 sorted. Being able to focus on our own specific jobs, that helps both of us."
The All Blacks coach Ian Foster has stood by his promise not to wrap his top players in "cotton wool", picking close to his strongest side possible for Saturday morning's clash with the Springboks at Twickenham, the team's final test before the World Cup.
Foster has largely stuck with the side that beat South Africa in Auckland last month, with blindside Luke Jacobson and lock Sam Whitelock replacing the injured pair of Shannon Frizell and Brodie Retallick, while Dane Coles takes over from Codie Taylor at hooker.
Mo'unga starts at No.10 in an unchanged backline from last month's win over the Springboks.
With their World Cup opener against hosts France in Paris just two weeks away, Foster said the All Blacks, who're unbeaten in 2023, want to maintain their winning momentum.
"The gap between our last test (Wallabies in Dunedin on 5 Aug.) and the France game (World Cup opener) is too big for us to use this as a cotton wool exercise.
"It's a great test match two weeks before a World Cup and the only way to go into the match is full throttle."
And Foster is adamant he's not worried about his players getting hurt.
"No, my heart's not in my mouth. It's a test match. Some things are part of the game. If you go in worrying about the consequences of that then you go in half-hearted and those things are almost guaranteed to happen."
While Foster isn't concerned, Richie Mo'unga isn't as nonchalant.
"I wasn't worried about it but seeing boys drop down like flies the last couple of weeks has got me worried. Not just for myself but worried for everyone. I guess with teams playing friendlies it's on everyone's minds."
Former All Blacks coach Steve Hansen's decision to help the Wallabies this week has also been on everyone's minds, with All Blacks hooker Dane Coles "gobsmacked" by the news.
Foster though brushed off concerns about his former boss linking up with the Australians and their coach Eddie Jones.
"Jeepers, surely we've got a better topic to talk on than Steve Hansen going to the Aussies for a couple of days with Eddie."
Foster said he knew of Hansen's plans a month ago and he approves.
"Outstanding. He's (Hansen) agreed to give me three pages of notes about everything that's going on in their campaign.
"I chuckle at the headlines. You guys must be pretty excited by it, but he told me a month ago he was going in. He's good mates with Eddie, but, there's no lack of trust around his commitment to us and to what we do and sharing stuff.
"I've got no issues really. In fact, we might bring him in for a couple of days ourselves."
While happy to joke about Hansen's involvement with the Wallabies, Foster won't be smiling if the All Blacks lose on Saturday morning or if any of his star players pick up injuries in their final game before the World Cup.
