Liverpool boss Kenny Dalglish believes Kieran Richardson should have been sent off after the Sunderland defender clipped Luis Suarez for their opening penalty.
It was the latest in a list of controversial incidents in fixtures between the two teams and Dalglish felt it raised the thorny subject of interpretation again.
"You don't want to see people sent off and I don't know what the rule book says about a clear goalscoring opportunity when Luis Suarez is one on one with the goalkeeper I don't see a clearer goalscoring opportunity than that," he said after the 1-1 draw.
"They may say he is taking the ball away from goal so it is a yellow card but if you are in the middle of the goal and want to go around the goalkeeper you have to go away from goal.
"I suppose nine-and-a-half out of 10 would have given Kieran the red card but we need to know where we stand and how they are going implement the rules and word them in the books - that is what we asked for."
However, Sunderland manager Steve Bruce felt ref Phil Dowd made the correct call.
"I thought the referee got it spot on," he said.
"I thought the goalkeeper was going to retrieve it and Suarez was going away from goal - but on another day it could have been a red card.
"I thought Suarez had knocked it too far and I didn't think he was going to get on to it and stick it in the back of the net.
"It was more of a clumsy challenge from Kieran and we don't want to see these red cards anyway, they spoil the spectacle so I think he got it right."
