Cardiff City boss Ole Gunnar Solskjaer was furious after their 6-3 defeat Liverpool.
Solskjaer was aggrieved by Liverpool's third goal, which came from a corner as Jordan Mutch and Kevin Theophile-Catherine were on the touchline waiting to return after receiving treatment for injuries.
"I think you should look at that rule," Solskjaer said.
"How can you defend a corner kick with nine men? Two of your men have not faked anything or dived, they just want to get on the pitch, two of them at the same time.
"I said to the fourth official 'they are going to score here, don't worry about that'. Two minutes they were stood there, or one minute 30 seconds he (fourth official) said, so you have got to look at that.
"You have got to look at the rule. We can discuss it all day long. Two of my biggest men were out of that corner-kick. It was the vital goal. We had been 1-0 up, 2-1 up, playing against a good team."
Solskjaer was enthused by his team's first-half display, and he added: "We had them exactly where we wanted.
"We tested them defensively and we scored some fantastic goals, and maybe we conceded two poor goals. Liverpool didn't have a lot in the first-half, chances wise."
