Manchester United manager Jose Mourinho has urged their fans to improve when the club face Liverpool in the Premier League at Old Trafford on Sunday -- telling them not to just "come to the theatre" but "play with us."

Old Trafford had a flat atmosphere inside it for much of the EFL Cup semifinal first leg against Hull City on Tuesday. United were not at their best on the pitch -- and that was met by quietness in the stands -- until Juan Mata broke the deadlock and Marouane Fellaini added a late second to secure a 2-0 advantage.

Speaking in his postmatch news conference, Mourinho said: "Maybe I didn't do my job well to prepare players for the game. Maybe I should bring more tension to the dynamic, preparing the game.

"The players have to improve, I have to improve and the fans also have to improve for a big match on Sunday. Today our performance was good enough to win but, on Sunday, we all have to improve.