Preparing for tomorrow’s Top 14 game against Bayonne, everything was organised around Juan Martin Hernandez, and then on the Thursday morning he comes in and he’s sick and he’s ruled out for the weekend.

That complicates the issue for Ireland more so than for Racing Metro. We’re all looking to maximise Johnny’s ability, because I think when he’s happy as a person, he plays his best rugby. When he left us for the Six Nations after the Toulouse game, he left in a great frame of mind. He was happy with his form going into Irish camp and going back playing with all his Leinster players and it just flowed for him from there. It flowed in those last two internationals.

For this week the plan was to use him in the group of 23 but all going well, he wouldn’t go near the pitch. Now that Juan Martin Hernandez is out of the equation it becomes very complicated. As we go to print we’re not too sure whether Sexton starts or whether he sits on the bench.

We’re also aware of the bigger picture with England the following weekend and Castres the weekend after that and then Italy and France in the weekends after that. It’s impossible for any human being to play all those games so Racing are trying to not use him at all, if at all possible.

If we can get our act together and beat Bayonne at home without him, the plan was to start Johnny in the Castres game, between the England and Italy matches. But if he starts on Saturday, which I don’t think he will, it further complicates the issue because some weekend is going to have to give and the weekends that won’t be given will be England and France.

There will be flexibility about whether he plays against the Italians in the Aviva but for Johnny, especially if there’s a Grand Slam there, as a 10 and the main man, he’d want to start that game, being the competitor he is.

I can completely understand that and if that was me, I’d be the exact same. When there’s only five games and you’re on a run of form in the green jersey and have that momentum you keep going and you’re on autopilot as opposed to playing against Castres, having to sit out the Italy game and playing the French game. That would be like starting all over again against France instead of tipping over lovely from week to week.

You can’t do that for the run of game I’ve talked about but at the same time, we’ve been planning all week as coaches, too. Then these things happen very quickly and we’re onto plan B already. I just hope we don’t have to go to plan C and start Johnny.

It was great to collect him at the airport this week and incredible to see the transformation from his return in November. To contrast it with how he was after the New Zealand defeat, he didn’t say much but it showed how much of a horrible place he was in and how seriously he took it.

This time, it was a great thing to see, he was bouncing out of the terminal and I’d say for the first time since he’s moved to France, in his eyes, the other people in the Irish squad were looking at him and saying ‘I’d love to have a crack at what that fella is doing’.

Up to now I’d say he’s been nearly ridiculed for making the move and it’s nice for him, I think, to change that view. I can’t say with the way we’ve been playing that his decision has been validated but that’s the challenge of it and from the amount both of us have learned in the last eight months, whenever you leave this place you’ll be a five times better person for it.

Just the adaptation process and what has been thrown at you here, you’d never have come across in a Leinster or Munster or Irish set-up. It’s just incomparable because there are far more complications moving to a culture where it’s not your first language and rugby over here is done differently.

I’m not saying the Irish system is far better, it’s just we’re so used to it and that’s what the biggest challenge is. We’re all shaped by our environment and a culture shock can be a good thing and for me and Johnny it’s great that we can get a taste of something different and that we’re embracing it.

There are very challenging days, no doubt about it. There are days when stuff gets lost in translation and for Johnny that’s frustrating as a player because he’s not always getting his opinion heard as much as it would be in an Irish or Leinster set-up. For me, on the management side of things, I’m involved in a lot more communication and it’s very interesting.

It was also interesting seeing the Welsh boys back at the club. What a contrast from the arrival of Sexton. Mike Phillips was down on Monday and Tuesday but by yesterday was back on top of the world. I said to him “you’ve been beaten out the gate but you’re the one fella who can turn in a bad performance, you come back a superstar” after his Twitter banter with Niall Horan from One Direction.

It’s amazing but I’d say the Welsh lads were in a bit of shock about what happened in the Aviva.

It sounds simple but the statement you make in the first 10 minutes, it’s very hard to alter the momentum of the game. Ireland won the first 10 minutes psychologically and it’s very hard to change that there and then.

Ireland were so focused on the breakdown and teams are struggling now with it, there’s such detail and aggression going into it and I don’t think teams have found an answer to that yet.

I don’t think Ireland kicked particularly well for the first 30 minutes and Johnny had one or two very average crossfield kicks to start with but after that everything was on the money and it changed the momentum of the game. Leinster would have had a very good phase-running game but for maybe the first time at Test level, Johnny used his kicking game to actually soul-destroy the Welsh.

Maybe it’s me as a 10 but you can never underestimate that ability to put the ball behind a team in their own 22. You could see it in the Welsh forwards, they get up and they’ve long faces as they’re having to try and run back for the lineout, while the Irish forwards are walking on air going there. Don’t tell me guys like Mike Ross, Devin Toner, Paul O’Connell, Peter O’Mahony don’t like to see that ball going down there, they were singing in the rain. They need that excellence and that kind of quality under pressure from their 10 and Johnny delivered.