Capello asks Chelsea captain Terry: Why John? Why?
Terry went public with his grievances on Sunday and indicated he was willing to raise them at a pre-planned team meeting at their Rustenburg base, even if they upset the Italian.
In the end, having found he had no support amongst his team-mates and having been politely informed challenging Capello was not a great idea, the 29-year-old backed down.
However, the damage was already done and Capello hit back on Monday night.
"This is the big mistake, this is the very big mistake," Capello told ITV1.
Clearly, Capello is incredulous that his authority should be challenged by a player - his captain until he stripped him of the honour in February over well-publicised personal issues - in a public forum.
"My door is always open. If people want to speak with me they can speak with me," added the Italian.
"Every time we have a meeting I ask the captain, problems? You want to say something? Never.
"Then I read yesterday that John Terry said this, I don't understand why he doesn't speak with me.
"When you speak you have to speak privately, not with the media.
"I think he is more disappointed. I know sometimes players want to speak more with you (the media) than with the other players.
"But the mistake is that you have to speak with the players, with me, with the dressing room."
That Terry put his dented pride to one side and joined his team-mates on the training ground this morning meant England avoided the kind of cataclysmic confrontation that has beset the French squad this week following Nicolas Anelka's expulsion.
Not that Capello viewed the two situations in anything like the same light.
He said: "No. This was not a revolution. It was one mistake from one player. No more."