Manager Alan Pardew was annoyed with referee Phil Dowd for sending Shola Ameobi off for dissent and for dismissing Paul Dummett for a late tackle on Luis Suarez.
Ameobi's red was the most bizarre of the two. The striker was booked for arguing with the referee just before the restart and he continued to shout at Dowd, which caused the official to send him off.
"I think what happened is he said 'if you carry on I am going to send you off' and maybe sarcastically Shola said 'are you going to send me off?' and he did," the Newcastle manager said.
"That is what Phil told me. He should have managed it better than that. It was a shame.
"I know Shola and he doesn't swear.
"It was sad because it might be his last match for us.
"How angry can you get if you don't swear?"
"The Paul Dummett one was just a yellow card. Brendan agreed with me."