Rested for the weekend, he had the chance to freshen physically and mentally for a prospective role in the second Test in Hamilton on Saturday with a reminder of the quality of Fiji's play.
"We knew what we were going to get and for those who didn't know, the New Zealand public who don't watch European rugby, these guys are rock stars over there. I was well aware of that, as was the team," he said.
"What happened was expected and they came with an intensity we expected."
It was good to have the opportunity to play them again in Hamilton, and to try and address issues revealed in the first Test in Dunedin, he said.
Having such a tough game early on in the Test campaign was good, especially for a young All Blacks team.
"It just opens doors for those guys to learn as much as possible, and Fiji are giving us that test at the minute, and this weekend it's not going to be perfect again.
"We'll learn some more, and that's the beauty of rugby, we get opportunities every week to learn and grow as players," he said.
"It's awesome for Fiji to be playing international rugby again. What they went through last year was really tough, playing one game in six weeks [on their Covid-affected northern hemisphere tour] and also for what their people are going through as well, giving hope was really important."
Based on what was seen in Dunedin, and knowing how they were performing for their European clubs, having Fiji Drua join Super Rugby would be good for the competition. It would also be great for the players who had the chance to play for them, whether from New Zealand or Fiji, he said.
Mo'unga said he had been enjoying watching fellow first five-eighths Beauden Barrett working on kicking drills he had developed while in Japan, especially his left and right-foot spiral kicking.
The art of spiral kicking was coming back, although he said he had still to master it.
"Our relationship is the same, we both have daughters that are a similar age and the rivalry continues for us, battling it out for the 10 jersey which is healthy and good for us both," he said.
Mo'unga said when he wasn't playing, it didn't reduce the nervousness he felt about games. And, as soon as teams were named, he switched to helping those who were playing the best he could so they were able to perform at their best.
"I prepare like I'm going to play, but your role changes a bit. You're really selfless in your acts about giving the starters, and the boys in the 23, every opportunity they can to learn and grow.
"I'm chasing balls left, right and centre, making sure the kickers have got them. It's just a real good experience to humble yourself again and give others a chance to prepare well," he said.