Former Manchester United No2 Mike Phelan feels his old club can shock Manchester City tonight.
City go into the derby 12 points ahead of United.
"One game changes things in football and this could be the night to do it," Phelan told talkSPORT.
"The motivation should be there in a game of this magnitude. Players go into a big game in the best frame of mind. This is where they earn their corn and it means so much to the city of Manchester.
"You would expect United to be really up for this because they have a lot to prove from what has been a disappointing season.
"I would never rule out Manchester United. They have still got very, very talented players. They have just lost their way a little bit, but the talent is there, the quality is there. It is just making sure the heads are on right when it comes to the big games.
"I would never rule United out in a big game at Old Trafford. They can upset any team. It depends on his selection and tactics but I would still favour Man United to upset the apple cart tonight."
