Carlo Ancelotti believes Louis van Gaal will find it “difficult” to make Manchester United title contenders again, with the Dutchman’s decision to implement a new system a further challenge for the new manager at Old Trafford.

Ancelotti, speaking before Saturday’s International Champions Cup meeting between his Real Madrid team and United, admires Van Gaal’s ability as a coach. But having won the Premier League and FA Cup double in his first campaign as Chelsea manager, in 2009-10, the Italian understands how tough Van Gaal may find elevating United.

Asked if the 62-year-old can transform United from last season’s seventh-place finishers to serious championship contenders, Ancelotti said: “It will not be easy to win in the first year because there are many competitive teams who want to win. It is not easy to implement a new system. It is important that the player is convinced but it is difficult to say how long it will take.

“He is a very good and very experienced manager, he has fantastic experience and he will do a fantastic job at United. He is a manager who has nothing to learn. After Ferguson, it was more difficult for United, but they now have to rebuild a team. They have signed good players but building a team is not easy and the Premier League is a very competitive league.”

Ancelotti confirmed that Cristiano Ronaldo would not face his former team at Michigan Stadium, which is known as the “Big House” and is 109,000 sell-out, as he is being eased back into action following a post-World Cup break.

“He has been working individually, separate from the team, but he will not play tomorrow and will train when back at Madrid because we will use him in the Super Cup,” said the coach. “The plan for Cristiano was right. We gave him one month of rest and started back on 26 July but he needs to recover completely and for this reason we don’t want to take a risk tomorrow.”

Of the match Ancelotti said: “It’s never a friendly against Manchester United. It is a fantastic team in a fantastic stadium but it is the last game of our tour and we want to finish well. We need to play a good game tomorrow because we play a fantastic team. I am not surprised by the crowd. The people here have a fantastic culture, they support our team and soccer is improving really quickly in the USA.”

Ancelotti laughed off the stories that he was on the shortlist, alongside Van Gaal, to become the United No1. “These are rumours that usually happen but I am at a fantastic club. I have lots of respect for United but I am happy here and I think they have made a good choice in Louis van Gaal,” said the 55-year-old.

On Frank Lampard’s impending loan move from New York City to Manchester City, Ancelotti, his former coach, added: “I didn’t know this. I’m really surprised because I thought he was coming here to play in USA. It’s too late for me to take him to Madrid but I’m really happy for Frank as I have a good memory of him. I wish him luck. He’s a good signing for Man City.”

If United defeat Madrid they are guaranteed to reach the International Champions Cup final which is on 4 August in Miami, where they could meet City or Liverpool. Madrid have no chance of doing so.