O'Gara stock rising higher
Sexton put in the groundwork which Carter is benefiting from
Jonathan Sexton would not be surprised to see Racing 92's Ronan O'Gara return to coach Munster or Ireland when the time is right.
"I think he has a real future in coaching," said Sexton.
"Then, you could see him coming back to Munster or even Ireland. You never know.
"He has done it the right way. He went away. He is building into it."
First, O'Gara has to take his ideas and turn them into trophies. The first real shot at glory will come on Saturday when Racing pursue the Champions Cup in Lyon.
It does seem curious that O'Gara was handed the role of defence coach when he built his stellar career on manipulating defences.
"I think his role should be what he's known for - his skills," voiced Sexton.
"Obviously, as an out-half, his expertise was in attack. If they gave him the attack, he would have more of an influence. He has been given the defence and you can see that is the most organised part of their game."
When the bigger picture is completed in at Racing, Sexton could just tur out to be their Michael Cheika.
The Ireland fly-half took two years to put in place the changed environment for Dan Carter to come in and prosper from.
Really, the comparison with Cheika falls on the fact Sexton never finished what he started, his two seasons leading to no trophies.
When Sexton entered the Paris club, there was a mess that had to be cleaned up in terms of professionalism and structure.
Does he feel Carter is reaping the reward of his groundwork?
"It's not for me to say. Look, that's for you guys to decide," he said.
"I know what happened when I was there. I can look back and say anything I did when I was there was for the good of the group. I tried my best and that's all I can say on the matter.
"I wish the guys well. I've got some really good friends who are still in the team.
"I hope they go on and do great things and I can look back on my time there and say I did my best."
The wallet of the owner Jacky Lorenzetti and his vision for the club convinced Sexton to leave Leinster in 2013 in order to transform potential into prizes.
"Yeah, I knew that when I went. I wasn't just going to sign for anybody," he said.
"I thought with the players we had signed for that season, we could have done something sooner than what was realistic."
Gradually, Racing have found their collective feet to stand 80 minutes away from European supremacy.
"It's always strange watching your old team," said Sexton.
"They have got some quality players in Chris Masoe, Dan Carter, Joe Rokocoko, three influential guys in the team."
It may be all Racing need.