The former Bhoys striker has been heaping praise on both the Scottish champions' head coach and winter recruits.
Indeed, the ex-forward, who recently interviewed Deila for BT Sport, was once one of the Norwegian's staunchest critics. Now, though, he believes 'only an idiot' wouldn't be able to see progress at Parkhead.
The Celtic boss's big problem, according to Sutton, was that he knew how he wanted to play - he just didn't have the players to fit his style.
And the arrivals of Mackay-Steven and Armstrong from Dundee United have helped massively towards that end, he says.
"Ronny knew how he wanted to play but he inherited players who didn’t fit the style and he’s had to mould his team and get his own boys in," Sutton told the Record.
"That’s not easy but if you look at the team now, only an idiot would think there has not been a lot of progression from the team at the beginning of the season to the way it is now.
"I’d say the signing of the boys from Dundee United in January have helped in that respect and the facts are Ronny could be about to become only the third manager in the history of the club to win the Treble."
Both featured (one substituted, one introduced in place of someone else) at St Mirren last night, when the Bhoys won 2-0 to take them eight points clear of second-placed Aberdeen in the Scottish Premiership.
It was James Forrest who opened the scoring for Celtic, though, while Stefan Johansen doubled their lead from the penalty spot.
Next up for Celtic is a league clash with Partick Thistle on Wednesday night, before a trip to Inverness Caledonian Thistle and then another home fixture against Kilmarnock.