All Blacks coach Steve Hansen's wake-up call to Steven Luatua in May served its purpose, the Blues loose forward conceded.
An unfit Luatua was singled out for extra fitness work during a training camp, and was pushed to near exhaustion by All Blacks trainer Nic Gill as the media and Hansen looked on.
Hansen also openly criticised Luatua for going "missing" in games because he was not fit enough to do the repeated efforts required at the top level.
"They were definitely some fun times," Luatua joked, after being named to start in Saturday's Rugby Championship showdown with South Africa.
"I quite enjoy running, especially with the coach on your back and Nic Gill making up drills just trying to smash you.
"But in terms of resolve I definitely think it did help me. They are looking for an All Black who can work through the pain and can find that resolve. I just needed a reminder."
Luatua missed the cut for the June series against England and has had just 10 minutes off the bench against Australia at Eden Park so far in the four nations tournament.
Now fitter than he was during his stellar 2013 campaign, the 23-year-old blindside flanker has finally been given an opportunity to start with Jerome Kaino (elbow) and Liam Messam (thigh) unavailable for the Westpac Stadium clash.
"He learned the hard way but he's learned a valuable lesson and hopefully he can carry that with him for the rest of his career," Hansen said.
"He's certainly worked hard and now we expect him to play that way."
Luatua's aerial skills were what won him selection, especially given lock Sam Whitelock (rib cartilage) joined Messam and Kaino on the sidelines.
Hansen had considered using dual opensides Richie McCaw and Sam Cane with number eight Kieran Read.
But the need to bolster the line-out with some height and another jumping option because of the challenge from Springboks locking duo Victor Matfield and Eben Etzebeth swung selection Luatua's way.
"The aerial skills were what we are losing with Sam [Whitelock] and Steven is very good in the air. Richie and Sam [Cane] aren't too bad but they are not in the same class as Steven. That was the major consideration," Hansen said.
The inclusion of lock Jeremy Thrush was the only other change to the forward pack from last weekend, while Aaron Cruden has recovered from his chest injury to reclaim the number 10 jersey from Beauden Barrett.
Cruden will face rising South African talent Handre Pollard, who will be playing just his fourth Test after getting the nod ahead of Morne Steyn at first-five.
Pollard is a more attack-minded player than Steyn and shows a willingness to take on the line.
"I imagine that Cruden will get a few people running at him during the course of the game. He's going to have to stand up and make his tackles," Hansen said.
The All Blacks coach said he did not think Pollard's inexperience would see him get overawed by what is expected to be an intense, physical battle between the world's top two teams.
"I remember when Dan Carter didn't have any Test caps and I was coaching Wales... he smashed us," Hansen said with a wry smile.
"[Pollard] had a great under-20 tournament. [Springboks coach Heyneke Meyer] has obviously got a lot of faith in him. You can see why when the kid plays; he's a pretty good player."