Cristiano Ronaldo has said that Ralf Rangnick must be given time to make his mark at Manchester United.

Rangnick has won four, drawn two and lost one of his seven matches since being appointed the club's interim head coach, but the recent performances have been disappointing.

Man United's top-four hopes suffered a blow when they lost 1-0 at home to Wolverhampton Wanderers in their last Premier League match, but the 20-time English champions progressed to the fourth round of the FA Cup courtesy of a 1-0 win over Aston Villa on Monday.

Ronaldo has said that Rangnick has "changed many things" since his arrival, and the Portugal international has insisted that the German needs time to implement a new brand of football.

"Since he arrived five weeks ago he changed many things. But he needs time to put his ideas across to the players," Rangnick told Sky Sports News. "It takes time but I believe that he is going to do a good job. We know we aren't playing the best football but we have many games to improve.

"Since he arrived I think in some points we are better, but he needs time. It's not that easy to change the mentality of players and the way they play, the culture, the system like that. I believe that he is going to do a good job."

Man United will be looking to make it back-to-back wins over Villa when they travel to Steven Gerrard's side in the Premier League for Saturday's late start.