Celtic moved nine points clear at the top of the Scottish Premier League with a hard-fought win over Motherwell.
Gary Hooper notched the crucial goal from close range just as it looked as though neither team would find the net despite a plethora of chances.
Moments earlier Tom Hateley saw his penalty saved by Fraser Forster after Kelvin Wilson's foul on Jamie Murphy.
It means Celtic head into the winter break with a commanding lead at the top as they seek to defend their SPL title.
Celtic started extremely brightly and looked like they'd gone ahead just two minutes in, when Georgios Samaras glanced Kris Commons' superb cross into the net, but the assistant referee's flag cut short the early celebrations.
That set the tone for the opening period as the home side bombarded Darren Randolph's goal.
Commons fired just wide from the edge of the box, Randolph saved a close-range Hooper shot, with Commons' follow-up well blocked by the under-fire Motherwell defence, and the keeper did brilliantly to tip Charlie Mulgrew's top-corner-bound free kick over the bar - all that within the opening ten minutes.
Motherwell, playing an unconventional back three, eventually forced their way into the match and the departing Murphy should have done better than to blaze over the bar from the edge of the box.
With eight minutes to go before the break, Murphy lost Kayal with a change of pace but his shot, intended to curl in at the far post, instead drifted wide.
That triggered another spate of Celtic chances, with Samaras having a header booted off the line by Simon Ramsden, Commons drifting a shot just over and Samaras again forcing Randolph to get down sharply to hold a shot from the edge of the penalty area.
But the best chance of the half came in the closing seconds.
Victor Wanyama headed a Mulgrew corner back across goal and Randolph failed to gather, but with the goal gaping, Ambrose knocked the ball over from underneath the bar.
The chances continued to flow as the second half got under way, with Wilson foiling Murphy with a terrific last-ditch challenge.
Randolph pushed Wanyama's deflected shot over and after flapping at the corner, the keeper saved well from Samaras.
As the game entered the final 20 minutes, play was ebbing and flowing like a basketball match and Motherwell earned a potentially match-winning opportunity when Murphy was adjudged to have been fouled in the box by Wilson.
But though Hateley's spot-kick looked well enough hit, Forster threw himself to the right to keep it out.
And Celtic made Motherwell pay when Hooper put them in front with 10 minutes to play, tucking Samaras's cross away with typical aplomb.
Though Motherwell competed well with Celtic, as several clubs have done so far this season, with a nine-point lead at this stage, the league title seems certain to remain at Celtic Park.
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