England's Football Association is to investigate comments made by Liverpool manager Brendan Rodgers on referee Lee Mason and his assistants in the wake of his side's 2-1 loss at Manchester City.
Rodgers may face an FA charge after he appeared to breach the regulations by calling into question Mason's integrity and implying potential bias after the defeat on Friday.
If you're working at this level you have to get it right. It's not even a difficult one.
Aggrieved that Raheem Sterling had a goal ruled out for offside and Luis Suarez was denied a late penalty, Rodgers questioned why Mason, of Bolton, near Manchester, was given a match involving a Manchester team.
"I was surprised we are playing in Manchester and have a referee from Greater Manchester - I am sure we won't get Liverpool-Man City someone from the Wirral," said Rodgers, in reference to the north-west peninsula area near Liverpool.
"Hopefully we don't have another Greater Manchester referee again on a Liverpool-Manchester game."
Rodgers said he thought all three match officials had a horrendous game.
"We never got any decision," Rodgers said. "I just felt the mistakes made shouldn't have happened at this level. This is a big game."
Rodgers called the decision to rule Sterling's goal offside poor.
"The linesman on the offside one - he wasn't even on the same cut of grass," the Liverpool manager said.
"If you're working at this level you have to get it right. It's not even a difficult one.
"It is a perfectly-timed run and he is given offside when he is through one-on-one on goal. These are big moments in big games."
Rodgers complained of another incident in the second half when Suarez was denied a free-kick on the edge of the box.
"Joleon Lescott came right through him and you can argue there was a penalty at the end," Rodgers said.
"Luis can't jump because he is tugging at his shirt."
City manager Manuel Pellegrini also found grounds for complaint.
His side now face a fixture against Crystal Palace on Saturday, 48 hours after the Liverpool contest.
However, key title rivals Chelsea, Arsenal and Liverpool have an extra 24 hours' recovery time.
"I'm not talking about having to play so many games because it is the same for all the teams," he said.
"But I think we should have at least 72 hours from one game to another.
"I'm not talking about Manchester United but all the other teams at the top of the table play 72 hours after.
"At this stage, we play so close (together), the rest of the teams must be the same."