Antonio Conte has warned Jose Mourinho not to engage in mind games or technical area bust-ups ahead of Chelsea's visit to Old Trafford on Sunday.
Mourinho was sacked by Chelsea after winning the Premier League title in 2014, with the club's form and league position drastically falling in the following campaign.
After a disappointing draw with Anderlecht in the Europa League quarterfinal, United will look to bounce back against Chelsea.
He admits, all the same, that his task at Stamford Bridge this season has been simplified by the club's non-participation in Europe but says that alone does not explain their dominance in the Premier League.
"It is frustrating. If we were really struggling football-wise and were miles away, then in some ways you can't accept it but you can see why you are struggling". For sure, we had more time to work with the team.
The likes of Spurs, Manchester City, Manchester United and Arsenal have all had to compete in either the Champions League or Europa League this season.
"They have a great team and everybody knows that".
"I have zero problem", he said. "We concentrate on ourselves".
"Of course [Chelsea] are much better prepared for the game than us". There are a lot of good signs. I want to try and win with my team.
"There's nothing I can do, they have to go until the end".
"As managers and players with one team you must give 100 per cent".
"But at the same time going on a run like we have done shows we have a bit of steel and have a bit of character about us".
"We analyse matches, we analyse opponents but to work on the pitch, with dynamism and intensity, at this moment is impossible".
"You have got more problems if you are struggling in games", Carrick added.
Mourinho had a less fantastical take on things when he spoke Sky's Soccer Saturday programme, and stated Ibrahimovic maintaining his current level next season would be excellent if he chooses to remain at United.
"So in that respect we are not in a bad place". It's not a friendly game, both teams want the three points and for this reason you fight to win. But if you ask me if I like it or not, I don't.