David Moyes insists he was not given enough time needed to succeed at Manchester United, saying he was "devastated" at his sacking.
"I was devastated to lose the job because it was something I felt I could make a real success of," he said.
"We knew it was going to take time to make the necessary changes. It was going to take time to evolve. But we were in the process of making other important changes. In the end, I don’t feel I was given time to succeed or fail."
"It was a step into the unknown and, looking back now, it was near enough the impossible job."
The 51-year-old endured a difficult 10-month tenure in charge at Old Trafford, as Manchester United suffered a number of notable defeats and finished with their lowest ever points tally in the Premier League.
The Scot claims he tried to sign Cristiano Ronaldo, Gareth Bale and Cesc Fabregas but the major signings needed to improve the squad did not materialise.
"It's been well documented that we wanted Fabregas, Bale and Ronaldo. There was talk of Ronaldo when I first arrived. We were close to getting a couple of major names.
"I'm not getting in a blame game here but things just didn't materialise."
The former Everton manager also revealed his disappointment at the manner in which his departure was handled, after news of sacking broke on a number of media outlets the day before.
"In the end it was difficult for my family, the way we discovered — via the media — that I’d lost my job," he told journalist Matt Lawton.
"We have always tried to do things the correct way. I know it comes with the territory, and I know if you lose matches you risk being sacked. But how it affected my family made it hard."
Moyes revealed he had met Sir Alex Ferguson on "several occasions" since his Manchester United departure.
It was claimed Moyes' attempts to contact Ferguson were unsuccessful when rumours of his imminent exit began to surface.
"I’ve met Alex on several occasions since I left. And I spoke to him about the days surrounding my departure. He explained it to me and I totally accepted what he said.
"He was in a difficult position, and I understood that."