Nottingham Forest manager Aitor Karanka apologised to the club’s fans after their 3-2 Carabao Cup defeat at Burton Albion.
Forest were out-fought at the Pirelli Stadium and Karanka said they could have no excuses for the defeat.
He told the club’s offocial website: “We had a chance to reach the quarter-finals for the first time in 25 years and it is a real missed opportunity. If we were complacent then that should never have been the case because we were playing to reach the quarter-finals.
“I’m really angry because a team from League One, a team which has played four games in ten days, has looked much better than us. They were much stronger and they wanted everything more than we did.
“I can’t understand why that was the case and I don’t want to say something that I’ll regret tomorrow. I just feel embarrassed and sorry for the supporters who travelled this evening because we all came here thinking we could achieve something good.
“We knew that as the Championship side we were going to control the ball but we needed to do more when we had it.”