Reminded of how Gibson had aired misgivings over his commitment towards the end of his time on Teesside, Everton's record £11million buy added an extra edge to tomorrow's Goodison Park reunion with his old club by snapping: "I think it's time he grew up."
"They said they didn't want to sell me, then, just before the window shut, they did want to sell me. I wasn't happy and wanted to leave. I wanted a new challenge, for a club with ambition, and I found one in Everton. They have a higher ambition than Boro.
"I was disappointed to hear what the chairman came out with, but that's life. He has his opinions and I don't hold anything against him, the staff or players. But to come out and say things like that - I think they have to grow up."
And he has no intention of following the trend of muted celebrations against former clubs should he find the target.
"Believe me, I will celebrate if I score against them." he said. "You have to move on. I know I made the right decision coming here."