David Moyes said that he had no inkling until this week that Sir Alex Ferguson was leaving Manchester United or that he had been nominated as his successor.
The outgoing Everton manager told a packed press conference at the club's Finch Farm training complex that he never doubted that he should take the opportunity and did not hesitate when it was offered.
He was shocked by it but had taken a "really big step" going from Preston North End to Everton in 2002 and that it was a similar step up to go from Goodison Park to Manchester United.
"I'm disappointed to be leaving such a great club," he said. "The club has been such a great part of my life."
But when asked if he had considered turning down United's approach, Moyes said: "I have to be honest and say no."
He insisted he had not been planning to leave, despite his contract running out this summer, and that he had been planning for next season.
"I wasn't planning to leave," he said. "My contract was running out but if you had pushed me, I would have said I would stay. Everything is in place for next season, pre-season has been arranged and the chairman knew what I wanted to do."
Regarding informing Bill Kenwright of his decision, Moyes said: "It has been very difficult. I have great respect for the chairman and have a great relationship with him. He is a really good guy. We had a difficult meeting on Wednesday but he totally understood." He confirmed that Kenwright had asked his advice over a successor.
Only once did Moyes speak specifically about the man he is about to replace, saying: "I don't think anybody thought the day would come when Sir Alex Ferguson retired. We all thought he was superhuman: he is an example to anyone in their 70s.
"The respect for him within the game is beyond any words I can use. We are from different eras. I grew up looking at Jock Stein and Sir Alex Ferguson. First I admired him and then, as the years have gone by, I have competed against him. I cannot say anything that would do justice to what he has done."
Moyes said he would understand if Everton fans were upset at the manner of his departure though he insists he will stand in the usual place in his dugout on Sunday for his last home game, against West Ham.
"Maybe the hardest part on Sunday will be at the end of the game, but I will be coming back to Goodison Park," he said. "I will not be away long. Hopefully on Sunday the fans will react in the same way they did when I first walked through the door.
"You can never tell with football fans. They support their team and I would understand it if they weren't happy. But I will be standing in the same position as I always have done, trying to see if we can take this outside chance of getting into Europe."