Martin O'Neill admits Lee Cattermole's red card was 'merited' after the Sunderland captain was punished after the final whistle in the 1-1 draw at Newcastle United.
Cattermole was shown a straight red card at full-time by referee Mike Dean after being deemed to have used foul and abusive language.
The midfielder had been booked inside the opening minute of the game at St James' Park following a challenge on Cheick Tiote and it was his 10th yellow card of the season.
Black Cats boss O'Neill did not quibble with Cattermole's red card, but did question whether Tiote should also still have been on the pitch after the Newcastle midfielder committed a string of fouls.
"I have gone in to see the referee and you can't be abusing the referee and therefore it has to be merited," O'Neill told ESPN.
"There were plenty of mitigating circumstances though. Tiote is a fine player but he was very lucky still to be on the field."
Sunderland had led at the home of their arch-rivals through Nicklas Bendtner's first-half penalty after Michael Turner had been fouled by Mike Williamson.
However, Stephane Sessegnon was sent off on 58 minutes for catching Tiote in the face and O'Neill had no complaints with that decision.
He added: "It's a sending-off offence and it hands the initiative to the opposition."
Visiting keeper Simon Mignolet then saved Demba Ba's penalty before an injury-time equaliser from substitute Shola Ameobi left O'Neill frustrated.
"I am very proud of the team and very disappointed to have dropped the points so late in the game," said O'Neill.
"We played brilliantly first half and deserved to be in front. But it is difficult to win a game with 10 men. We defended resolutely and it was a terrific effort."