In-form Motherwell striker Kevin van Veen ended Celtic’s long winning run with a second-half equaliser at Parkhead.
Callum McGregor put Celtic ahead with a deflected long-range strike as they looked to add to their 17 consecutive victories and 21 successive domestic home wins.
But the cinch Premiership leaders allowed Van Veen the chance to show his threat just after the break and the Dutchman obliged with his ninth goal in six matches and his 20th league goal of the season.
Motherwell held out to move a point closer to Premiership safety as Celtic dropped points for only the third time this season.
Ange Postecoglou’s side can still break the points record of 106 set by Brendan Rodgers’ Invincibles side in 2017 – if they win their five remaining matches.
Celtic, who had Cameron Carter-Vickers back in their team following a knee problem, moved 13 points ahead of Rangers, who travel to Aberdeen on Sunday for their final game before the split.
Motherwell had the first chance when Callum Butcher volleyed over after Joe Hart’s unconvincing punch, but Celtic soon settled into their usual dominance without cutting their visitors open.
With Tomoki Iwata starting again, McGregor had licence to get forward and he curled just over before setting up Daizen Maeda for a headed chance which Liam Kelly stopped.
The skipper had no second thoughts about shooting when he received the ball 25 yards out in the 24th minute and Dan Casey’s attempt to block inadvertently took the ball out of Kelly’s reach and into the bottom corner.
Maeda missed a half-chance and Sead Haksabanovic shot straight at Kelly from 22 yards as Celtic remained on top for the rest of the half.
Kyogo Furuhashi turned Casey and scuffed wide just after the interval but the move proved costly to Motherwell as the Irish defender injured himself and had to go off for Shane Blaney.
The game changed in the 55th minute when Celtic left Greg Taylor one-on-one with Van Veen and Callum Slattery’s swift ball forward allowed the Dutchman to get up a head of steam. The striker turned one way and the other and lifted the ball beyond Hart.
Motherwell soon had a chance to go ahead when Paul McGinn was allowed a free header from a corner but the ball just drifted too far in front of the defender to get a proper connection.
Kelly made an excellent stop from Furuhashi following Matt O’Riley’s through ball before Van Veen displayed his skill and confidence by skipping past several opponents and firing a shot from 25 yards which Hart got down to hold.
Furuhashi was booked for trying to punch the ball into the net before Kelly saved headers from Carter-Vickers and Carl Starfelt.
Oh Hyeon-gyu headed wide from three yards as the game entered the closing stages and Starfelt headed over from the final chance.