s to a late goal from debutant Callum McGregor
The Norwegian's first competitive game since taking over from Neil Lennon last month saw Kris Commons, Leigh Griffiths and substitute Teemu Pukki hit the woodwork before 21-year-old McGregor, making his first competitive start for the Hoops after impressing in pre-season, drilled a low shot past Stefan Magnusson with seven minutes remaining.
"I am happy that we won the game but most happy with the performance," said Deila.
"I love to win, I am here to win but I need performances
I want to win in a certain way as well.
"Today was a step forward in the way we want to play and that is what I am most happy about.
"If we had won and played s*** then I would be more irritated than if it had been 0-0 today because I know that we are going to score goals in the next leg.
"We deserved it, we deserved more
I am getting energy out of this
I like what I saw in the second-half."
On McGregor's performance, Deila said: "I think he did well in his debut, in an important match like this.
"He has big talent but I want him to be more direct, go more forward and link up more with the full-back but that will come and I am very happy for him that he scored a goal."
McGregor had a productive loan spell at Notts County last season and was delighted with what he claimed to be the biggest goal of his career so far and now he is looking to stake a claim at his boyhood heroes.
The Scotland under-21 midfielder said: "To score in a Champions League for Celtic - I have been there since I was nine years old - was a dream come true.
"It was a little bit of relief with it being 0-0 but I was absolutely delighted.
"It was a big night for the club to strive to get Champions League football again and that might be the goal that takes us through to the next round so I am absolutely delighted.
"To get the win was excellent for the team and on a personal note to score the winning goal was unbelievable
I am still pinching myself to see if it's real.
"I spent last season with Notts County in League One and I feel I have come back a better player
I feel that I am mentally ready to make the challenge.
"When you come back here you don't want to leave it
Being at Celtic means the world to me so if I can be here for a long time I will be delighted.
"There will be delight tonight and tomorrow but once I come in on Thursday I will get my head down and get working and strive to be better every day."
KR Reykjavik boss Runar Kristinsson was hoping his side would hold out for the draw but insists the tie is not over ahead of the second leg at Murrayfield next week, which is being used as Celtic Park is out of commission due to the Commonwealth Games.
He said: "It was a bit disappointing but I think it was a fair result.
"It is still alive, 1-0 is nothing in football
It is going to be very difficult but if we can defend well and go to Scotland with a good attitude we believe we can do something there, at least give them another game because I think we did that today."
Source : PA
Source: PA