Sunderland manager Steve Bruce insisted referee Lee Mason "guessed" when he decided not to award his side a penalty in the 1-0 defeat at Manchester United.
Assistant referee Jake Collin indicated a spot-kick for handball as United's Nemanja Vidic rose to challenge Ji-Dong Won, but the decision was reversed to give a free-kick to the hosts.
"You can't be guessing on penalties," said Bruce.
"It took me three or four looks on the video to see who handled it."
Even though the right decision was made, Bruce was still left in disbelief at Mason's perceived gamble to overturn the penalty award.
"Eventually he gets it right so we can't argue, but if you watch the referee's reaction he's got information that it's a penalty and goes towards the spot," he said.
"Then he is surrounded by United players and eventually changes his decision."
Sir Alex Ferguson, who celebrated his 25th anniversary at Old Trafford with a victory, believes justice was done when Mason reversed the decision.
"I couldn't believe it because I clearly felt it was the Korean boy who handled it," he said.
"The fact he (Collin) has put his arm across his shoulder, it's a penalty kick.
"I don't think Lee Mason had any idea why, and you saw how the players reacted, and he's given the correct decision."
Meanwhile, Bruce's disappointment deepened as he revealed striker Connor Wickham may face a lengthy lay-off with a knee ligament injury.
"That's the big disappointment as we think it's a serious knee injury," said the Black Cats boss.
"This means we have had seven serious knee injuries in the last 12 months. It's an early diagnosis but we think it's ligaments. We hope the scans aren't bad but I'm afraid it doesn't look good."