United have endured a difficult start to their first campaign without Sir Alex Ferguson at the helm since 1986, losing three games out of six in the Premier League.
He told The Telegraph: "There was always going to be that moment when Sir Alex Ferguson retired.
"Who was going to take over, what was it going to be like when a new manager came in, were they going to be the same force as they have been over the last 20 years?
"They will be because they are Manchester United. There's a transitional period that will happen but David Moyes is a very good manager."
Moyes's quest to turn things round at Old Trafford continues this evening with a trip to the North East, as United take on struggling Sunderland at the Stadium of Light.