London - Derby boss Phillip Cocu believes Wayne Rooney's experience and insider knowledge will be "extremely important" when they play his former side Manchester United in the FA Cup fifth round.
Now Derby captain, Rooney is United's all-time top goalscorer after a trophy-laden 13 years at Old Trafford between 2004 and 2017, and he has had a big impact in both a playing and coaching capacity since arriving at Pride Park in January.
"Of course Wayne is very important, and maybe even more so in this game because he knows Manchester United like no-one else," said Cocu. "He knows the players, the level of performance, what is needed in those big games. So yes, it will be extremely important for us on Thursday."
Rooney's arrival has helped the Rams pull clear of the Championship relegation zone and Cocu believes the focus on the former England captain helps ease the pressure on some of the younger members of his inexperienced squad.
"I think it could be important for the rest of the team," he said. "He's used to the big games, he's used to the attention.
"So maybe it will only have a positive influence on his performance, I think. But if you're not used to playing these kind of games, it's better that the attention goes to more senior players and you just focus on your task and your job in the team."
Cocu also praised the impact Rooney had made as part of his coaching team.
"He joins in with the technical staff in preparation for games, to analyse the opponent, to select the clips we want to study," added Cocu.
"I always ask his opinion not only for this game because he obviously knows the club very well, but I think this is the way we work. He is a player, that's the most important, and he wants to play, but he's also very involved in the team tactics and how we approach the game.
"So yes we'll use that for this game, and we won't change that."