Rashford, 18, has burst onto the scene at Man United in recent months, most recently scoring a superb solo goal in the 2-1 win over West Ham United in the FA Cup on Wednesday.
Ronaldo joined United as a youngster in 2003 and developed into one of the best players in the world before leaving for Real Madrid in 2009. Van Gaal rubbished comparisons between the two in his pre-match press conference ahead of the clash against Aston Villa on Saturday.
“You can compare apples with pears so I don’t agree with what you want to suggest – we have to wait and see,” he said.
“It is fantastic what Marcus has done so far, but you cannot compare him with Ronaldo, who also played in a different position. He was not a striker when he was at Manchester United, I believe.”
Rashford has enjoyed a remarkable start to his United career but Ronaldo is one of the best players to have ever played the game.
It is important that expectations are kept low when it comes to Rashford as too much hype, too early, could cause him to get carried away.