Liverpool manager Brendan Rodgers has claimed that Manchester United defender Jonny Evans should have been dismissed with Jonjo Shelvey during Sunday's 2-1 defeat at Anfield.
Shelvey was shown a straight red card from referee Mark Halsey at the end of the first half after he and Evans threw themselves into a challenge for the ball.
"If Jonjo Shelvey gets sent off than so should Jonny Evans," Rodgers told BBC Sport. "I am bitterly disappointed the referee only saw one side of that.
"I thought the best team lost. What you can't control is decisions by the referee. The players were outstanding."
Sunday's loss means that Liverpool are still without a win after five games of the new season.