Ange Postecoglou's Celtic closed to within four points of league ladders Rangers with a controversial goal from Kyogo Furuhashi enough to give the hosts victory over Hearts in a close encounter at Parkhead.
The Japan forward looked like he was marginally offside when he converted Anthony Ralston's cross in the 33rd minute but Bobby Madden and his officials awarded the goal.
Celtic had other chances but Hearts came back strong after the break with Barrie McKay causing a number of problems before missing an excellent late chance in an exciting finale.
The 1-0 victory closed the gap on Rangers who won by the same score against Hibernian 24 hours earlier following a much-debated penalty award.
Celtic had Carl Starfelt and Tom Rogic back in the team following injury while James Forrest also came in.
Socceroos playmaker Rogic played a full game which would have pleased former Australia boss Postecoglou.
Celtic started brightly. Starfelt headed wide before Hearts had a huge let-off after David Turnbull robbed Cammy Devlin.
Craig Gordon spilled Jota's resulting shot but Forrest stabbed the loose ball against the post from close range.
Jota twice shot over the bar from outside the box, Ralston was too high from a half chance and Gordon tipped Callum McGregor's deflected effort wide.
Hearts were attacking when they could and Joe Hart was called into action when Craig Halkett got a shot away following Stephen Kingsley's free-kick.
The opener came after Ralston ran round the outside of Rogic and drilled in a cross which Furuhashi turned home at the near post.
The Japan international was ahead of the Hearts defence and replays suggested he was also slightly ahead of Ralston when the right-back struck the cross, but offside appeals went unheeded.
Hearts defender Kingsley had a brilliant chance when he ran untracked to the near post to meet McKay's corner but he cut his header too thinly and it flashed beyond the far post.
Forrest had a great chance to settle matters in the 84th minute when he was played in by Furuhashi but Gordon saved and Hearts were soon away on the counter-attack.
Substitute Gary Mackay-Steven looked set to score but he stumbled and McKay shot just wide from the loose ball with Hart stranded.
Australian Associated Press