Former referees Howard Webb and Keith Hackett have said Manchester United's Wayne Rooney should have been booked against Liverpool while the home side's equaliser should not have stood.
Zlatan Ibrahimovic headed home in the 84th minute to cancel out James Milner's first-half penalty as Sunday's match ended 1-1 at Old Trafford.
Ibrahimovic's leveller came after Antonio Valencia had strayed into an offside position in the build up, while Rooney had earlier conceded a free kick after catching Milner with his studs but was not cautioned by referee Michael Oliver.
Webb, who refereed the finals of the World Cup and Champions League in 2010, said in The Times: "I think Wayne Rooney's tackle on James Milner, for which Michael Oliver gave a foul and no more, is one of those that is somewhere between a red and a yellow card.
"Looking at the video, which Oliver did not have the chance to do, I would ultimately say it is a yellow card. Rooney's tackling technique is poor, and he is reckless, but he puts his foot in the direction of the ball and does so with less than the excessive force that would make it a sending-off offence.
Webb added that he believed assistant referee Mick McDonough should have raised his flag before the home side's leveler, saying: "Because he is too far down the touchline, he cannot judge whether Antonio Valencia is just offside before he receives the ball, which he is. In those circumstances, he gives the benefit of the doubt to the attacker. He will have known he lost his position at a crucial time."
Former Professional Game Match Officials Board general manager Hackett said in The Daily Telegraph, on behalf of You Are The Ref: "Wayne Rooney was also fortunate to escape a caution for a foul on James Milner that was over the top of the ball and potentially very dangerous. Michael didn't have the greatest of views but he should have spotted it."
Of United's goal, Hackett added: "When Michael and his team look back on the game there will be three decisions they will be disappointed with.
"The most serious of them was when assistant referee Mick McDonough failed to notice Antonio Valencia was offside in the build-up to Manchester United's equaliser. He was completely out of position and it was a poor error considering the move was being conducted at walking pace."