The Hoops picked up a second successive win in the Scottish Premiership with a 2-0 victory over Ross County on Wednesday evening, and remain 16 points behind leaders Rangers with three games in hand.
Neil Lennon handed Turnbull his 14th league appearance of the season, and the 21-year-old repaid his manager’s faith with the opening goal and a stellar all-round display at the point of a midfield diamond.
The Scot took a while to find his feet at Parkhead following a summer move from Motherwell, but has started in both of the Bhoys’ last two league matches, as well as last weekend's Scottish Cup triumph over Hearts.
Reflecting on Wednesday’s win over Ross County during an appearance on BBC Sportscene, Stewart was quick to praise the midfielder for the progress he is making in Glasgow.
"He's a top drawer player”, the pundit said.
“I think everyone recognises that, and he’s coming to the fore.
"You can see that he’s growing in confidence and in stature within the team itself.
"Throughout the game he started to link really well with the front two.
"Now, whether they’re going to stick with that formation we don’t know, but there were some really good bits of passages of play.
"It had some speed in it as well, which is something that Celtic have not had enough of this season.”
Turnbull has three goals and three assists across all competitions for the Hoops so far this term.