Newcastle United manager Alan Pardew has declared his anger at referee Mike Dean's decision to only book David Luiz after the Chelsea defender hauled down striker Demba Ba when seemingly through on goal.
The Magpies lost 3-0 at home to Andre Villas-Boas' men on Saturday, with Didier Drogba, Daniel Sturridge and Salomon Kalou each scoring after Frank Lampard failed to convert a first-half penalty.
However, the main talking point was the official's controversial decision not to send-off Luiz, with the former Southampton and West Ham boss claiming had one of his player's committed a similar foul at Old Trafford, they would have faced an early bath.
He told reporters: "I thought he was going to get sent off. It was the fourth minute of the game but it doesn’t really matter when it happened. He was in on goal, he was behind Luiz and the goalkeeper wasn’t going to get to the ball.
"Therefore it was a goal-scoring opportunity and he brought him down. I could not understand why he didn’t send him off. I was quite angry about it because if that happened at Old Trafford to one of my players they would have walked and I thought he would have walked."
The 50-year-old called for clarification on the rule, dismissing Dean's claim that Ba did not have control of the ball as an excuse for only brandishing a yellow.
He continued: "The referee said to me at half-time that he did not have control of the ball and I am not quite sure of the rule book so need to get that out and have a look at it. I don’t understand that rule because there seems to be some clarity about that rule.
"If you have got a goal-scoring opportunity and the defender brings you down from behind you go off. There was no man covering so I don’t understand.
"Then it is a different game altogether and with the atmosphere we had, Chelsea would have struggled."
Pardew did manage to find some positives from the game though, applauding the effort of his players and Tim Krul's display in particular, which included a Lampard penalty save.
However the Englishman was left to rue a first-half injury to captain Fabricio Coloccini, with centre-back partner Steven Taylor also forced to withdraw from the game despite the home side having used all three substitutions late into the second-half.
He added: "Outside that decision it was pretty tight, they bossed periods of that first half and we didn’t have the impact I would have liked.
"Losing Fabricio Coloccini with a thigh injury was another blow we had to take, but we still wouldn’t lie down so I have to applaud my players and we almost got something out of the game.
"The players were terrific in their attitude. No Coloccini, no Gutierrez or Cheick Tiote and we still pushed Chelsea so there are a lot of positives to take out of that.
"We also lost Steven Taylor what looks like to have a bad [achilles] injury and conceded two late goals. You have to feel for one or two of our players, not least Tim Krul who was absolutely brilliant and the penalty save was fantastic."