Nicolas Kuhn scored his first goal for Celtic but pre-match dissent from the visiting supporters at Pittodrie was amplified as a strong second-half performance from Aberdeen earned the hosts a point.
Celtic ran out to chants of “sack the board” and a banner which read “Celtic board, on your heads be it” as the fans expressed their displeasure over the club’s transfer window business.
Their team had a goal disallowed and hit the bar twice in a one-sided first half but Bojan Miovski gave Aberdeen the lead with their first effort at goal in the 50th minute and his 19th goal of the season.
German winger Kuhn levelled in the 64th minute in his second appearance for Celtic but the game remained in the balance and the 1-1 draw ended a run of six consecutive wins for the cinch Premiership leaders since they lost back-to-back games in December.
Aberdeen had first-team coach Peter Leven in charge following the sacking of manager Barry Robson and he handed a first start to the club’s sole January signing, on-loan Crystal Palace midfielder Killian Phillips.
Celtic had both of their new signings, German winger Kuhn and on-loan Norwich forward Adam Idah, on the bench as Maik Nawrocki replaced the injured Cameron Carter-Vickers.
The defender’s ball over the top earned Celtic their first real chance and Luis Palma was celebrating after converting the rebound from Liel Abada’s saved effort. The Honduran winger was clearly offside though, however it took the VAR team several minutes to disallow the goal.
Celtic continued to create a steady stream of first-half chances. Kelle Roos saved comfortably from Palma and Abada and the former missed a great opportunity after Alistair Johnston’s cross found him in space on the corner of the six-yard box. His shot hit the top of the bar and went over.
Paulo Bernardo lobbed a delicate effort over a crowded goalmouth and off the top of the bar as Celtic continued to dominate. They had 13 first-half shots at goal, but only three on target with Matt O’Riley and Alexandro Bernabei off target just before the break.
Aberdeen had barely managed to get the ball in the final third but they re-emerged from the interval with a new-found vigour and quickly turned defence into attack when a Celtic move up the left broke down.
Dante Polvara’s forward pass set Miovski up to run at Nawrocki and the striker shifted the ball inside before curling home from 18 yards.
The game was transformed. Aberdeen threatened from a series of set-pieces with Celtic blocking several shots and Phillips almost made himself an instant hero with an audacious 45-yard chip which had Joe Hart beaten but just drifted off target.
It was another recent signing that was soon celebrating though. Kuhn and Idah came on along with Anthony Ralston in the 59th minute and the winger soon made his mark as he cut in from the right, played a one-two and then got the ball back from Idah before shooting in off Nicky Devlin.
Both teams went all out to get ahead. O’Riley saw a deflected effort hit the outside of the post and Hart saved from Connor Barron after Nawrocki’s poor clearance.
The offside flag went up after good chances at either end and Graeme Shinnie looked all set to score only to hit Hart with his shot. Leighton Clarkson looked offside from Shinnie’s header before he got the ball back.
Miovski was definitely offside when he beat Hart to Clarkson’s low cross and knocked the ball into the net from close range.
Celtic finished strongly but Roos came off his line to foil O’Riley and substitute Stephen Welsh headed over with the last action of the game before the away supporters resumed chants against the board while applauding the players.
