David Moyes has been accused of "ignoring the advice" of more experienced Manchester United staff and making a series of fundamental mistakes because he did not realise that leaving Everton to replace Sir Alex Ferguson was like "going from a yacht to a cruise liner".

René Meulensteen, one of the coaches who left after Moyes took over, said Ferguson's successor had only himself to blame for being sacked because he had "under-estimated" the size of the job at Old Trafford.

Meulensteen described it as "too crazy for words" that Moyes had left United seventh in the Premier League, 23 points off the top, and blamed it on Ferguson's successor trying to make too many changes too quickly. "You have to look at Manchester United and the job that David Moyes took on," he said. "United were a very successful team, with many successful years behind them. The strategies in place worked. But David ignored the advice that was given to him by many of the staff in place at the time.

"He opted to put his own plans in place, which he was perfectly entitled to do, but I think it backfired on him. I always strongly believe the performances and the results are a reflection of what is actually happening behind the door and that wasn't good enough, as simple as that.

"Don't forget David was a respected manager in the Premier League who worked for 11 years at Everton in a very good way. But I did warn him: 'Do you realise, after everything at Everton, you're going from a yacht to a cruise liner? That's how big the difference will be.' It's not just necessarily the work on the pitch. It's everything that surrounds Manchester United, the players, the performances, the pressure, the style, the identity. And I think he underestimated that. It's always easy in hindsight but unfortunately it's cost him his position."

Meulensteen believes Moyes's first mistake was to bring in so many coaching staff from Everton, a decision that eventually persuaded the Dutchman to leave the club. "It became very evident to me after a few meetings with David Moyes that he wanted to bring in his own people and do it his own way," he continued. "I felt very strongly that things would change dramatically for myself and the position I held so I didn't feel there was a good foundation to carry on."

He added: "It's too crazy for words. I've been part of Manchester United's backroom staff for the last five years for Sir Alex Ferguson and the last five years have been proven to be the most successful in the history of Manchester United. Now they've had a poor season, they have dropped to seventh, out of the Champions League and suddenly, after so many years of constant success, we're now asking whether Manchester United are good enough to get in the top four. To me, there should be nothing else and that's probably why the decision has been made because they want to be back [in the Champions League] and next year they want to be challenging for the league title.

Meulensteen, speaking on SiriusXM FC, backed Ryan Giggs's appointment as interim manager but believes there will have to be an extensive rebuilding process in the summer. "Five, six, seven players [have to be changed] and that's too much … that is the challenge the club are facing in the summer but I still think United have a fantastic squad and with the right additions can be a force very quickly."