David Moyes: Mourinho, Klopp and Ancelotti would also have struggled if they followed Fergie

The Scot, who is now Sunderland boss, joined the Old Trafford club after his countryman retired following a trophy-laden 27 years. However, Moyes was fired ten months into a six-year contract in 2014 and was replaced by Louis van Gaal, who also struggled and was eventually sacked at the end of last season following an FA Cup win.

This season, Jose Mourinho has also started slowly with a recent run of form lifting the club to sixth in the table. But Moyes, who will come face to face with the Portuguese in the Premier League match on Monday, insists he has few regrets.

"The only regrets would be the time, only the timescale," he said. "But I think most people looking back at it and me myself would say I don't think whoever had taken over from Sir Alex would have had an easy ride.

"Whether it had been Jose then or Carlo Ancelotti or Jurgen Klopp or Pep Guardiola or David Moyes, I think it would have been a difficult job for whoever took over.

"I was definitely unfairly treated. Over the piece, other managers have come and gone and it's been difficult for them as well. I think it would have taken whoever it was time to change the squad around.

"They had great players, Manchester United - there were one or two who were getting near the end of their careers. It was gong to be a little bit of a rebuilding job and it was never going to be done immediately."

Moyes does not look back bitterly on his time at the club but believes it is a unique place in which to be in charge. He added: "They have got a very good manager in charge just now, they had a very good manager and experienced manager in Louis van Gaal, and I think they would all say going to Manchester United is a different animal than maybe even some of the clubs they have managed before.

"It's disappointing that I didn't get to see out my contract, that's for sure, but I'll look back knowing that I was really fortunate that I had a chance to work with some great players, I got a chance to see how at the real top level, things are.

"The big thing is I enjoyed being at Manchester United. It was a great football club, it really was."

Moyes will be without midfielder Jan Kirchhoff on Monday after the German underwent surgery and will be out for three months.

"Jan had an operation during the week to repair his lateral meniscus. At the moment we think it'll be close to 12 weeks," added Moyes.

Defenders Javier Manquillo, Billy Jones and midfielder Steven Pienaar are back in training, but Moyes said he had not yet decided if they could feature at Old Trafford.