He failed to do so in 2013 when Jantjies had a season at the Stormers.
Understandably, the now-25-year-old lost his dad that year and went through a difficult time.
But it was on the pitch where he was judged by the Newlands faithful and the feedback wasn’t good.
Jantjies, though, is back to his best at the Lions where he’s got a licenCe to thrill.
Coetzee, meanwhile, is an old-school kind of coach - at least, he used to be at the Stormers. A good one at that.
He puts a lot of emphasis on the halfbacks being the decision-makers and running his game plan - meaning there is little room for tierlantynkies.
Injured pivot Handre Pollard is the one who perhaps suits Coetzee’s style of coaching a little better.
Maar die een se dood is die ander se brood.
And Jantjies is taking his chance at Super Rugby level.
On Saturday against the Stormers, he showed a maturity in his game that will excite Coetzee.
And this bodes well for their possible reunion.
With Jantjies now a shoo-in to start against Ireland, it will be interesting to see who the other flyhalf in the Bok squad will be.
The Sharks’ Pat Lambie is on the road to recovery after suffering a shoulder injury during pre-season.
And if fit, he will most likely be in the squad.
Coetzee can also look overseas for a player like Johan Goosen and he even mentioned something about Morne Steyn at some stage last week. Let’s hope not.
Then you’ve got the Stormers’ Jean-Luc du Plessis. He is not ready for international rugby yet.
But what he has shown is that there is a new breed of pivot in the country.
Du Plessis, like Jantjies, is the sort of flyhalf who likes to try things.
And perhaps this is the way forward for the Boks.
Back to Jantjies, he’s had a taste of what it’s like to play under Coetzee and he will know exactly what the Bok coach will expect of him.
At the same time, Coetzee knows Jantjies’ strength and is not the sort of coach who will select a player and not allow him to express himself - within the “system” that is.
As for the scrumhalf position - another key decision-making area, it will be interesting to see who Coetzee opts for.
At least in this position there are a number of choices.
Surely, the days of Ruan Pienaar are numbered in the Springbok jersey - especially with 2019 in mind.
Then you have the likes of Cobus Reinach, Rudy Paige, Faf de Klerk and even Nic Groom battling for that position.
De Klerk proved to be a real terrier when he took the field against the Stormers on Saturday, but the fact that he is not currently in the starting XV at the Lions should be of concern to the national boss.
All indications are that we will see a new Bok halfback combination in June and the challenge for Coetzee is to get the perfect duo and to get them to implement his game plan.
For now, De Klerk and Jantjies look like a good combo.