Gerrard 'concerned' by Rangers disciplinary issues
The manager saw Alfredo Morelos sent off after warning about discipline.
Rangers boss Steven Gerrard says it's hard for him to defend his players after seeing his team pick up their eighth red card of the season.
Gerrard revealed he had told his players about the importance of maintaining discipline after Scott Arfield was dismissed against Hearts on Sunday. But that warning failed to prevent Alfredo Morelos from being sent off for two yellow cards on Wednesday night as Rangers were beaten 1-0 by Aberdeen.
Scott McKenna had given the Dons the lead at Ibrox but Derek McInnes' side were reduced to ten men after half an hour when Sam Cosgrove collected his second booking.
Rangers' numerical advantage lasted until 19 minutes into the second half when Morelos caught Graeme Shinnie with his arm and was given his marching orders, much to Gerrard's frustration.
"I'm concerned," he said. "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."
Gerrard even suggested his side was lucky not to have another red card, with Kyle Lafferty not taking heed of his yellow card.
"I'm very disappointed in our performance," the Rangers boss 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."
Aberdeen manager Derek McInnes was delighted with his side's response to losing the League Cup final on Sunday and said he couldn't understand why Sam Cosgrove was shown his red card.
"We had to pick ourselves off the floor after Sunday but I was pleased with a lot of the aspects of the game,"he said. "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."