Manchester United boss Louis van Gaal has been refereeing in training to teach his players to "control their aggression" against Liverpool.
Van Gaal's fourth-placed side face the team in fifth in the Premier League at Anfield on Sunday (13:30 GMT).
Only the Merseyside derby has yielded more red cards in the Premier League era - 20 to 15 - than the United-Liverpool fixture.
"Control of emotion is also a talent," said Dutchman Van Gaal.
United go into the game off the back of a 3-0 home win over Spurs.
Liverpool have won their last five league games to lie just two points behind United and four adrift of second-placed Manchester City.
Rooney's barren run at Anfield
In 10 games he has played at Anfield, Wayne Rooney has found the net just once - and that was a decade ago.
But Van Gaal does not think the striker has a mental block.
"It's strange, but it can be like this," said the former Netherlands coach.
"He's a very experienced player, he has played on all the grounds in the world, so I don't think that he shall be influenced by the fans at by the stadium or something like that."
Van Gaal on English sides exiting Europe
Van Gaal has also given his reaction to the lack of Premier League representation in the quarter-finals of the Champions League or Europa League this season.
He believes English sides are hampered because they don't get a winter break, while players in other leagues, like Germany, Spain and Italy, do and are "much fresher" when the knock-out stages start.
"That, in my opinion, is the difference because players need rest," said the former Barcelona and Bayern Munich coach.