Steven Doris' dramatic late equaliser for Arbroath means Celtic will have to replay their William Hill Scottish Cup fourth-round tie against the third-tier side following the 1-1 draw.
With one eye on Wednesday night's home Champions League Group G decider against Spartak Moscow, Hoops manager Neil Lennon made nine changes to his side. The hosts nevertheless went ahead in the 35th minute when Stewart Malcolm hammered a clearance from the byline off the back of fellow Red Lichties defender Alex Keddie and into the net.
The SPL champions created and missed a host of chances while also being foiled by Arbroath goalkeeper Scott Morrison, but with four minutes remaining Doris shocked the home side when his deflected drive beat Lukasz Zaluska in the Celtic goal.
The procession towards the visitors' goal began from the first whistle and in the third minute Hoops striker Nicolas Fedor Miku headed a Joe Chalmers corner over the bar from six yards.
In the 20th minute Victor Wanyama drove wide of the far post from distance and moments later captain Scott Brown looped a header over the bar from another Dylan McGeouch cross.
After surviving all those Celtic attempts on goal, Arbroath gifted the Hoops the opener. Defender Mark Baxter and Malcolm combined to dispossess Miku on the far side of the box and the ball appeared to be running over the byline for a goal kick.
However, with the whole of Celtic Park to aim at Malcolm attempted to hammer a clearance up the park but succeeded only in hitting the back of Keddie and the ball rebounded into the goal.
The home side kept piling forward with relative ease after the break, with Rabiu Ibrahim curling the ball past the far post after being set up by Adam Matthews.
The visitors began to tire as the second half progressed and they were let off in the 67th minute when Miku worked a yard of space inside the box before rifling a shot off the junction of bar and post.
In the final 10 minutes Arbroath kicked on and after Thomas Rogne had conceded a free-kick 30 yards out with a foul on Derek Holmes, Doris' drive took a defection before nestling in the back of the net.