I'm convinced he knew he was staying a long time ago, if you look at the fact noone was in the frame, the signings we're going for even before he signed and his smirk everytime he was asked the question, they were just waiting until the right moment, winning the cup provided exactly that, as did the mini run at the end of the season.
This club has no bottle when it comes to making things happen, they're opportunists that take adavantage of situations to soften the blows of those decisions.