Celtic boss hails impact of midfield maestros
The midfield pair, who made a blistering start to their Celtic careers with goals on their debuts following their transfer from Dundee United last January, have seen their development at Celtic Park stall this season due to injuries and a loss of form.
However, a double from Mackay-Steven and a solitary strike from Armstrong saw the Hoops restore their six-point advantage over Aberdeen at the top of the Scottish Premiership table.
Celtic have been reliant on the goals of top scorer Leigh Griffiths in recent games and Deila was delighted to see the midfielders get on the scoresheet and relieve some of the pressure on the Scotland striker.
"Leigh had his chances today and could have scored but it's very important that we have other players scoring goals, wingers especially," the Celtic manager said.
"You need to get into the box between the posts; that's where 90 per cent of the goals are going in from and today we had them many times in there and they got their goals.
"I think both of them played very well. Gary has been out for a while now and has played two very good matches. Stuart looks very sharp so I'm very pleased with that.
"It's tough here and we have many players who haven't played in big clubs before and are coming from smaller clubs.
"It's one thing to come in and everything is positive but then the expectation comes over you and it takes time to deal with that and everything that comes with being a part of a club like Celtic.
"When you get through that you play with more freedom and hopefully now Gary has done it and Stuart looks much better as well.
"To develop players takes time but if you work the right way you get your credit in the end."
Armstrong's goal was his first since August and the player expressed his relief at ending his goal-drought.
"You could probably see the relief on my face when it went in. It's just nice to be back playing well and winning games as part of a good Celtic team right now," the Celtic midfielder said.
"Maybe I was thinking about it too much when my performances were a bit inconsistent but I think right now it is back to basics and concentrating on what I can do to help the team.
"I think as an attacking midfielder I always want to score goals and create goals but I've mainly been concentrating on getting my performances back to where I know they can be.
"Leigh Griffiths has done terrific over the last few months and got a lot of important goals for us at important times so it's nice to see other people chipping in with goals and of course from a personal point of view to get back on the score-sheet was important for me."
The win means Celtic, who face Ross County in the League Cup semi-final next Sunday, will hold a six-point lead over Aberdeen ahead of their top of the table clash on February 3.
However, Deila was keen to play down the significance of the tie at Pittodrie.
"It's always important to win games but it isn't finished now. It's finished in May so there are many, many games left to play," the Celtic manager said.
"We just have to keep on producing good performances and train well like we have done lately."