Everton boss Ronald Koeman feels the side must do everything possible defensively to stop former Toffees striker Romelu Lukaku.
Lukaku who left Everton for United during last transfer window, will welcome his former teammates to Old Trafford in a Premier League clash on Sunday.
During his time at Everton, Lukaku scored 53 goals in 110 appearances for the Merseyside club.
“We know him really well. He is a great finisher, and I hope we know how to defend him. But there are a lot of qualities around him, but in the box he is dangerous, fast and strong,” Koeman said in his pre-match press conference on Friday.
“If we defend like we have the last few games, maybe it’s his afternoon.”
Koeman said new signing Sandro Ramirez, who was bought as a replacement for Lukaku, will come good despite early struggles in his Everton career.
He said: “It’s not the time for frustration. You can’t do anything about it at this time. Yes, it’s different in possession now for us if you have a target man up front. It gives the team time to get up, we have different types of striker with Dominic and Sandro.
“Sandro needs time. He has pace, yes, but he is not the strongest yet. But it’s too easy to talk about the striker. Defensively we are making mistakes and that’s not the job of the striker.”
Former Southampton boss Koeman stated that former United striker Wayne Rooney has a big role to play in the Everton team, while stressing that the former England skipper has paid his dues.
“He has nothing to prove, of course not,” Koeman added.
“Everybody knows his quality. He’s one of the players who needs to react and bring the level of the players we expect from players like Wayne.”
And on Everton’s 3-0 loss to Serie A side Atalanta in the UEFA Europa League on Thursday night, Koeman said: “It was a short night. But of course after that game and that result, of course you have thoughts about the team, about individual performances and what we need to change.
“Even in a tough period that we played Chelsea, Man City, Tottenham, Sunday is Man United… there are different sides to look at. But of course, yesterday night I was really disappointed in the way we lost in the first 45 minutes. We lost the game in the first 45 minutes. Maybe even lost it in the last 25 minutes of the half.
“I saw the team with a lot of doubts, one of our strengths of last season was we had a good defensive organisation. And we lost our strengths at the moment.
“If you lose that against the big teams in the Premier League… but last night was painful as they (Atalanta) showed more ambition, more aggression and the space we gave their strikers was a big difference.”