Ole Gunnar Solskjaer has said Manchester United are receiving fewer penalties as a result of referees being influenced by rival managers.
United were held to a 0-0 draw by Chelsea at Stamford Bridge after referee Stuart Attwell opted not to give the visitors a 14th-minute penalty following a handball incident involving Callum Hudson-Odoi which he was asked to look at on the pitchside monitor.
Former Chelsea boss Frank Lampard and Liverpool manager Jurgen Klopp had previously questioned the number of spot-kicks United have been awarded.
Klopp claimed United "had more penalties in two years than I've had in five-and-a-half years at Anfield."
United have had eight penalties this season, two more than Liverpool, but Solskjaer said those comments have had a negative impact on his team.
"They probably thought his [Hudson-Odoi's] hand was in a very natural position when he flicked the ball," Solskjaer said.
"It's gone now. We should have had a penalty and that's clear. I'm a bit concerned that we don't get those penalties after what noises were made a month or two ago about us getting penalties. So clearly there is a point of managers influencing the referees which they shouldn't do.
"That's just the nature of us as managers isn't it, that anything that goes against you, you probably want to highlight. If something goes for other teams, you'd like to try to stop that probably. But I trust the referees not to be influenced by it.
"I was very surprised by the decision today when I looked at the video. Live, I didn't think it was a penalty so I can understand why he didn't give it straight away but when you look at the video, it is not a very natural position to have your hand in."
Attwell decided that Hudson-Odoi did not motion towards the ball with his hand but defender Luke Shaw added that the officials were also concerned by the backlash.
"I don't know. At the time I saw a handball. I didn't know if it was Mason Greenwood or Callum Hudson-Odoi. I just carried on. I didn't even know there was a VAR check. I don't know why they stopped it. If it was a penalty... but if they didn't think it was a penalty I don't know why they needed to stop," Shaw told Sky Sports after the game.
"The referee even said to [Harry Maguire], I heard him say: 'If I say it's a penalty then it's going to cause a lot of talk about it afterwards.' So I don't know what happened there.
"[Maguire] said they got told it was a penalty. They got told it was a penalty by VAR so... I'm not sure. I don't understand. If he's going to stop then you think he is going to give a penalty. We had the ball, we were attacking so it's confusing with this VAR.
"If it's not going to be a penalty they might as well just carry on the game and not stop the flow of the game. It was another one, that look, I'm not going to moan about it because I don't think either team did enough to win."
United later said that Shaw misheard Maguire's comments about the referee.
Chelsea manager Thomas Tuchel played down the incident.
"I was surprised and I'm still surprised because I didn't see live where the penalty should come from and when we checked on the pictures that we have on the bench from our iPad, I could not see any incident that should qualify for a penalty." he said.
"Maybe I have to look at it again. Until now, I don't know why it should be a penalty."