Substitute Leigh Griffiths' dramatic late strike gave Celtic a barely-deserved 1-0 win over Partick at Parkhead.
The Hoops striker had missed the previous four matches with a calf injury but replaced Nadir Ciftci for the start of the second half after a dismal first 45 minutes from the home side.
Ronny Deila's men continued to struggle, with midfielder Nir Bitton sent off in the 67th minute after picking up his second yellow card of the afternoon.
However, in the 89th minute Griffiths pounced to fire the ball into the net and take Celtic three points clear of Aberdeen at the top of the Ladbrokes Premiership.
It was cruel luck on Thistle who suffered their first defeat in seven matches but, after failing to win his last four home games, a huge sigh of relief for Deila.
Befitting a side who had finished the year in such good form, the Maryhill men looked comfortable and indeed confident in a low-key start to the match as Steven Lawless sent a dipping effort from 25 yards past the far post.
The champions' response was a drive from Callum McGregor which sped wide of the far post before a Tom Rogic drive from outside the box was saved by Jags keeper Tomas Cerny.
However, this was no assault on the Jags goal - though there were loud Celtic claims for a penalty when Rogic's shot from inside the box was blocked by defender Liam Lindsay. Referee Stephen Finnie was unimpressed and the game limped on.
Ciftci had the ball in the net but was flagged offside before boos from the home fans accompanied the half-time whistle.
Deila put on top scorer Griffiths for the start of the second half in place of Ciftci but the nervousness in the Hoops defence - especially when Efe Ambrose was in possession - gave Thistle continuing encouragement.
James Forrest replaced Rogic in the 64th minute to more boos from the increasingly disgruntled home fans, who were stunned soon afterwards when Bitton, booked in the 61st minute for pulling back Stuart Bannigan, was sent packing after a late shoulder challenge on substitute Gary Miller.
The dismissal stung Celtic into action. Forrest had a powerful drive beaten away by Cerny, who then denied Griffiths twice as the home side tried to increase the pressure.
As opposed to settling for the point, Thistle pushed forward for a goal and they came close when defender Dan Seaborne's header was cleared off the line by left-back Kieran Tierney.
But with a minute remaining Kris Commons' drive from the edge of the box was deflected high up into the air and fell kindly for Griffiths to volley past Cerny and into the corner of the net.