Crystal Palace boss Alan Pardew fears Wayne Rooney's current frustration makes the Manchester United captain "dangerous" ahead of their Premier League clash on Saturday.
The Eagles host United at Selhurst Park on Saturday with Rooney's performances coming under increasing scrutiny.
The England skipper has scored just two Premier League goals this season and missed a penalty as United crashed out of the Capital One Cup at home to Middlesbrough on Wednesday.
But Pardew expects Rooney to answer his critics and knows Palace will have to be on their guard, saying: "I think Wayne, throughout most of his career, has been at the top of the pitch or just back one in the No. 10 role.
"He plays both roles very well. He is at the top of the pitch now and maybe he is not getting the service he would probably want in that.
"I can see a little bit of frustration in him but that makes him dangerous. Rooney has proved many times -- particularly when he gets criticism -- that he can deliver.
"We'll be on our guard for Wayne. He's an outstanding player, he's the England captain and we'll give him the respect he deserves."
Palace have lost their last three matches, with the 5-1 Capital One Cup exit at Manchester City coming on the back of league defeats to West Ham United and Leicester City.
Injuries have hit them hard, but Pardew hopes to have the likes of Joel Ward, Connor Wickham and Marouanne Chamakh back to full fitness after the international break.
"We have Manchester United and then Liverpool, so this little run is a real test," he added. "But I still think if a bit of fortune had gone our way we could have picked up points. There is a lot of good news in the background here in terms of the injuries we have had.
"If we can pick up some points in the next two games I'll be really happy, then we will be well set for Newcastle after the international break.
"I'm looking forward to Manchester United. It will be a great occasion. We are very proud to have them here for the third year running, it's the first time that has happened, and it's about time Crystal Palace beat United.
"It's going to be important that our fans stick with us, particularly after a couple of defeats and with the way United play. They lull the stadium and take the positivity out of it by keeping possession. We have to keep it bubbling along.
"If we can stay in the game until the last 15 minutes we have a chance of winning it."
Jason Puncheon returns for Palace after missing out at City through illness, but Yohan Cabaye needs a late fitness check.