Manchester United boss Sir Alex Ferguson believes striker Wayne Rooney is on the verge of becoming a serious world-class player.

The 23-year old will appear in his 50th European match when United take on Wolfsburg on Wednesday night and Ferguson is confident that if he keeps improving at the rate he is, he will join the top echelon of players in world football.

Asked if Rooney could follow his former teammate Cristiano Ronaldo by becoming World and European Player of the Year, Fergie said: "That's the challenge for every player now, not just Wayne.

"But there are some great players out there. Kaka, Ronaldo and Messi are the best three in the world right now and I think Wayne can get to that level if he keeps making progress.

"European football is a challenge. It is the best teams and every player has to try and reach that challenge in a sense of their stature in the game.

"Wayne has had some fantastic games in Europe and, to be honest, he's also had some disappointing ones because it's not an easy competition.

"He has played a central role for us this season and will play central again against Wolfsburg."