The Hoops’ hopes of a clean sweep ended in some controversy against Inverness at Hampden Park on Sunday when they lost 3-2 to Inverness.
Celtic and their fans were enraged by referee Steven McLean’s failure to award a penalty against Caley Thistle defender Josh Meekings when he used a hand to prevent Leigh Griffiths’ goal-bound header just before the interval with the Hoops leading 1-0.
Celtic released a statement on Monday revealing they were “seeking an understanding” of the failure to penalise Meekings, who was since been served with a Scottish Football Association notice of complaint and the offer of a one-game ban which will see him miss the May 30 final against Falkirk.
After watching goals from Gary Mackay-Steven and Virgil van Dijk take the Parkhead side eight points clear of Aberdeen at the top of the table – Jim McAlister scored a late consolation for Dundee – the Norwegian said: “I am very pleased with the boys and I am proud of them. The disappointment was there from Sunday but we got rid of that.
“It was the toughest day in my career on Sunday, I have to admit that.
“It was very tough. I really wanted it (the treble) and I think we had a very good opportunity.
“So Sunday and Monday was very, very tough but now it has gone. I just want to keep on winning games and get that league title to Celtic Park.”
Deila was able to joke that he sat at home and “looked at the wall – and some television” but took no pleasure in Meekings’ predicament.
Inverness will “vigorously defend” their player in his appeal at Hampden Park on Thursday.
FIFA’s head of referees, Jim Boyce, entered the fray by saying that the Scottish FA is wrong to suspend Meekings and the Hoops boss said: “It doesn’t help us if someone gets banned. I don’t think that’s right.
“I don’t think he did it on purpose, the ball was going very quickly. It was reaction, but it was a clear hand ball, a red card and a penalty.
“I hope that he will play, the best players should always play in the final. I don’t think it is a positive thing to ban anybody.”
Dens boss Paul Hartley claimed some decisions by referee Calum Murray and his officials were “quite bizarre.”
He said: ” We had one in the first half and the referee gave offside and the linesman didn’t. He made a mistake and admitted that to me at half-time.
“I thought we were good. We just lacked a little cutting edge. If we’d scored the goal 10 or 15 minutes previously we’d have had them worried.
“Two set-pieces have done us in. I thought we worked well, we were well organised and there was good discipline to our performance. But Celtic have quality throughout their team.”