Manchester United boss Sir Alex Ferguson says they cannot take Arsenal lightly tomorrow.
Fergie has warned his players they would be foolish to think Arsene Wenger's side will be anything but a stiff test at Old Trafford.
He said: "Arsenal have still got forwards there who can hurt anyone: Van Persie, Walcott, Arshavin, Rosicky, Bendtner and Chamakh.
"It is easy for me on Sunday to have my team prepared because they know themselves they are playing a team with some quality.
"We have to be at our best, no question."
