Deila is now witnessing the same development with Boyata, Bitton, Virgil van Dijk and Charlie Mulgrew reacting to opportunities created by Commons, Stefan Johansen, James Forrest and Stuart Armstrong from rehearsed moves.
The Celtic manager observed: “There are a lot of World Cup Finals and Champions League Finals won by a set-play. It’s part of the game and 33 per cent of goals scored come from one.
“When there is a lot of tension, like on Wednesday, set-plays are very important.
“That is our strength, Scottish football has always been physical and we have to use that for set-plays.
“We should be dominant. Every time we have a set-play, every team we meet should be worried about our height and power.
“I remember Celtic’s 2003 team, opponents were scared to give away corner-kicks. I take that as a positive, so it’s as important as counter-attacks or offensive play.
“You have to be good at it and last year we had a very good record from set-plays. We had something like 23 goals from set-pieces and only lost two. That’s very good.”