Jose Mourinho has called on Manchester United's supporters to make life difficult for any visiting teams.

As the Red Devils prepare to host Southampton at Old Trafford on Friday night, the Portuguese has urged fans to be in full voice so as to act like a 12th player on the pitch.

"If, at Old Trafford, a couple of thousand away fans can be more noisy than 70,000 at home then we're in trouble," he said.

"It means there is no connection. Everything starts with the relation between team and fans.

"If the fans feel that connection — they want to play. If the fans play, then there is no chance for the opponent."