Steven Gerrard admits he is struggling to defend the behaviour of his Rangers squad after his warning about cutting out red cards was ignored by simmering striker Alfredo Morelos.
The Ibrox boss sat his squad down in the wake of Scott Arfield's senseless sending-off against Hearts on Sunday and told them it was time to brush up their act.
But the message did not get through to Morelos, whose inability to control his emotions saw him dismissed as Aberdeen handed Gerrard his first home defeat since taking over in the summer.
Scott McKenna fired the Pittodrie side ahead early but Gers were given hope when Sam Cosgrove got himself sent-off for the Dons just after the half-hour mark.
But as the Light Blues put in a dismal display, Morelos' frustrations boiled over as he caught Graeme Shinnie to earn a second yellow 19 minutes into the second half.
Gers have now collected eight reds this term and Gerrard admits his patience is running thin.
The manager – whose side have now surrendered top spot just three days after taking the title-race initiative – said: "I'm concerned. There's only so much I can do. I've made it very clear they're not helping themselves.
"They're making their task a lot more difficult. We miss key players for important games.
"It's very difficult for me to back them and protect them because 24 hours after a team meeting about controlling discipline, it's very tough for me to take right now."
McKenna crashed home a left-foot volley after seven minutes but Aberdeen had to battle on for the final hour a man down after Cosgrove was given a second yellow following a collision with Jon Flanagan.
Morelos' lack of control saw the numbers evened up but Gerrard confessed his side was lucky not to finish with nine.
"I'm very disappointed in our performance," he said. "Tonight was a really good opportunity and a difficult test for us – but one that I had confidence that I could pass. Unfortunately we've failed.
"Alfredo's first yellow for me is a little bit soft but it was probably a foul. The second one he deserves. But it's not important – we've got another red card which is hugely frustrating.
"We could've had another one. Lafferty's on a yellow but he is giving a foul away and gives away another – you're leaving the referee with an opportunity to make it nine."
Victory was the perfect pick-me-up for the Dons as they bounced back from losing Sunday's Betfred Cup final to Celtic.
"We had to pick ourselves off the floor after Sunday but I was pleased with a lot of the aspects of the game," said boss Derek McInnes. "It's a real shot in the arm when you see the players put so much in. There was tenacity all over the pitch. We got our just rewards.
"It was a real blow going down to 10 men. I've seen the red card again. Cosgrove gets the first touch. It was a coming together. If anything it was a foul to us.
"I find it astonishing that he has been sent off for that. He won't be getting fined. He's nothing to be sorry for."
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