The former Celtic striker is now full of praise for the Norwegian.
Chris Sutton has hailed Ronny Deila for his recent achievements with Celtic, according to his regular column in the Daily Record.
Sutton was critical of Deila earlier this season, after the Norwegian's career at Parkhead took a far from dream start.
Slowly, however, it appears the 39-year-old has won the former Celtic striker round.
Now, Sutton is full of praise for how the Bhoys boss has unified his squad and the Celtic supporters. Everything from Deila's fist-pumps to his public discussions about how he motivates his players have impressed the columnist.
And the ex-forward believes Deila's approach has made a 'big change' from his work earlier in the season.
"Deila spoke of being as one, treating the players as adults and big characters," Sutton said.
"It’s a big change from telling them what to eat earlier in the season but his ways are working. Deila has got everyone on board and it is clear as day.
"I don’t know if the fist-pumping after games was pre-meditated to spark a response but it’s brought the fans and the boss together, too. Everyone at the club seems to be pulling in the one direction and that can only be encouraging for the supporters who can now see a glorious ending to a campaign which started with concerns."
Celtic beat Dundee United yet again this afternoon, making it three wins out of four against Jackie McNamara's men.
The Bhoys will no doubt be relieved to know they are finally playing someone else in their next clash, as their bid for a domestic treble heads towards a potentially 'glorious' conclusion.
Celtic will face Inverness Caledonian Thistle in the semi-finals of the Scottish Cup, while they travel to St Mirren for their next Scottish Premiership action.