Ole Gunnar Solskjaer believes Manchester United great Wayne Rooney will be a threat in Thursday's FA Cup clash against Championship side Derby.
Rooney, United and England's all-time top scorer, will line up against the club where he enjoyed so much success when lining up for the Rams at Pride Park.
Rooney joined the second-tier side as player-coach after a stint in the United States with DC United and former team-mate Solskjaer is wary of the 34-year-old's threat in the fifth-round clash.
"He gave absolutely everything for this club and we all appreciate that," the Norwegian manager said. "But any goal he scores against us will be chalked off his goal tally. He doesn't want to score too many of them.
"He's a threat, in and around the box, set plays, and of course this game Wayne will show what he can do and he wants to prove that there's still fight in an old dog.
"We've got to be on our toes, don't give him any space in and around the box or in midfield."
"At the latter end when he played in midfielder, you can see he's got Scholesy-like passing range," he added, in reference to former United midfielder Paul Scholes.
Asked if Rooney is underappreciated in some quarters, the United boss said: "He's been a fantastic player for Man United and he played here for so long, he's the club's top scorer, he's won so many trophies.
"For me, I don't think the fans underrated him. I think everyone really, really appreciates what he did for us.
"He's still very welcome, he's still around the place, he still comes to Old Trafford. He will get a good reception from our away fans in that game definitely."