Fergie:
''Sadly, Roy Keane has a hamstring injury and that's unfortunate so Alan Smith will play there and it will be a big night for him,'' said Ferguson.
''A player like Riquelme is a major opponent and very skilful. He controls the tempo and everything goes through him.
''Alan can expect to be busier than he was against Manchester City on Saturday but I have a lot of confidence in him.''