Rangers manager Graeme Murty has slammed his side for failing to do the basics right in their 3-2 defeat by Celtic at Ibrox.
The hosts were twice ahead via Josh Windass and Daniel Candeias but still lost out to their Old Firm rivals, who went down to ten men in the game.
The visitors had Jozo Simunovic sent off for elbowing Alfredo Morelos but were still able to pick up all three points thanks to substitute Odsonne Edouard's strike.
"The people on the pitch had more than enough experience and opportunity to go and win that and we've managed to throw it away," Murty told Rangers TV.
"I'm immensely frustrated for the fans and the players because we put ourselves in a right good situation... I don't think we'll ever give ourselves a better opportunity to go and win the game.
"We started brilliantly and then lacked composure, got carried away with the atmosphere. They got back into it with a good hit from them but a poor goal from us. It then took 15-20 minutes for us to re-establish our composure.
"We go ahead again and then we concede an awful goal a minute before half-time. That's a fundamental flaw, an error that shouldn't happen at this level.
"The sending off is obviously a pivotal moment and after that we lost composure in possession. We started lumping crosses in from deep rather than playing through - and once again, we give away a really, really poor goal. Basics cost us today."