Ten years ago, Jose Mourinho would have had a fit if Chelsea had let one of his star players, who was still considered one of the best in the business leave the Bridge and go to a rival.
He would simply not have believed such a move could be countenanced. While it would not have been a resignation issue, there would most certainly would have seveal very loud and brutally viscous conversations to be had with the power brokers at SW6.
Fast forward and try to read between the lines of Mourinho's timid acknowledgment of the acceptance of Petr Cech's move to Arsenal.
"I always said I wanted him to stay but I understand Petr needed to move on to play first team football every week. Sometimes you have to respect the wishes of someone who has earned so much respect with his service and actions for your club. I support the owner’s decision to honour the player in this way.
"It is very rare in football to make a decision like this and for that reason I am proud of my club for making it. There are not many clubs in the world big enough to be able to make that decision.
"Petr’s success at this club will always to be remembered and we thank him for everything he did."
Ahh, ain't that sweet.
Cech responded with apparent mutual respect: "He, (presumably Mourinho) had to make his decision at the start of last season, I had to make my decision at the start of this season but I will always keep the best regards for him because I believe that we had so much success and so much respect for each other.
"He is one of the best managers in the world. Now, we will be opponents but it will not change our relationship, I believe.
"I learned a lot from him and one of those things was that if you have to make a hard decision, you need to make sure that you do it if you believe it is the right choice."
If, as seems likely Arsenal mount a serious challenge for the title and cup, then Mourinho will at some point revert to default mode. He has been at pains since his return to SW6 to maintain the loved-up feeling. But in the cold hard light of day, in the bruising and unforgiving, unrelenting pressure that comes with trying to keep the Blues afloat at the top, he will make his true feelings known.
Perhaps it won't come to that. Perhaps Arsenal will stumble along, grasping at fourth spot in the league and a dabble at at domestic cup.
Perhaps Chelsea will simply be too strong again next season and romp away with the league.
mourinho doesn't like perhaps, he likes certainty or as daman as close as possible to it.
Giving one of your best players to a rival only undermines that certainty.
Mourinho knows it, the Chelsea board knows it.
Should things go pear-shaped on the pitch for the boys from the Bridge, then Moirimho has a ready-made excuse.
Now, of that you can be certain.