Ronny Deila says Celtic’s lack of improvement over the last six months made up his mind to leave Parkhead at the end of the season.
The Norwegian’s imminent departure was announced in a statement on Wednesday and came after the Hoops were beaten by Old Firm rivals Rangers in a penalty shoot-out in Sunday’s Scottish Cup semi-final at Hampden Park.
Celtic are eight points clear of Aberdeen at the top of the Premiership with five post-split games remaining, the first against Ross County at Parkhead on Sunday.
Deila, who took over in 2014, said at the club’s Lennoxtown training comple: “It has been a tough week, there has been a lot of thinking and it hasn’t started this week either.
“I have been thinking about this for a while because I haven’t felt the team has got the results they should have and, maybe more importantly, the performance and improvement I wanted.
“When I came in to the job I talked about improving the team and playing attractive football and I think the last six months we haven’t had the improvement that we need.”
Now that the speculation about his future is over, Deila is looking to end his time at Celtic Park by clinching his second, and the club’s fifth, successive title.
The former Stromsgodset boss said: “Improvement is one of my biggest values and when you don’t get it, it kills me inside and I lose energy with that.
“I don’t think there has been a lot of improvement and when you don’t get improvement the outside pressure is going to get harder and harder as well.
“I have no problem dealing with that, I have been sitting in this room a lot of times and there has been a lot of difficult questions.
“That is not the problem, the problem is when you don’t get improvements and the things you said you wanted to create when you came in the door, you haven’t created.
“One of the reasons we haven’t had that improvement is because of the pressure and speculation around me all the time.
“That is why I think it is best for the club that new energy is coming into the club next season and now we can really focus on winning the five games and getting five (titles) in a row.
“It is going to be a huge thing for me, the players and the whole club, this is why the decision has been made.”
Much has been made of Celtic’s unwieldy squad, with speculation as to whether Deila was behind all the signings, but he took full responsibility for recruitment and will leave the Glasgow club with no hint of bitterness.
He said: “I know there has been a lot of speculation around this as well.
“One: I sign the players so don’t think about that. There is not one player who came in that door that I didn’t say yes to.
“Two: I knew what I came into when I took this job. This club wanted to be drifted in a positive way and have a positive economy. That was said before I came here and is being said now. I have no problems, I had unbelievable communication with the board, with Peter (Lawwell, chief executive) in bad times and good times.
“That is why I am not a bitter man.
“I feel that I have been given the chance and I felt lately we haven’t had the development we wanted in the team.
“I don’t have any problems with the players, I can look everyone in the eye and they can look into my eyes.
“It is easy to say this player is bad and this player is bad. The responsibility is with the manager.
“The players here are good and if you don’t get the best out of them, then you have to look at yourself in the mirror and I have done that.”