Record signing Arne Engels and Luke McCowan scored their first Celtic goals to maintain their winning start after Hearts were controversially denied a penalty.
Belgian Engels, who completed his £11m move on deadline day, fired home from the spot in the second half after James Penrice was penalised for handball.
Hearts striker Lawrence Shankland saw his header come off Liam Scales’ arm before the break only for VAR to overturn the penalty decision.
McCowan saw his ball go in off the post just eight minutes after he came off the bench, with Adam Idah’s stoppage-time goal ruled out for offside.
It is the first time Celtic have won five league matches without conceding since 1907, while Hearts are bottom of the Premiership with one point.
Celtic continue perfect start
Engels was chosen ahead of Paulo Bernardo after making his debut off the bench against Rangers two days after joining from Augsburg.
The midfielder twice came close in the first half, arriving in the box at the right time to fire wide in the third minute and hitting the inside of a post after a good flick by Kuhn.
Kyogo Furuhashi missed a great chance with Gordon rooted to the spot moments after being clattered by the Japanese striker.
Referee Colin Steven pointed to the spot in the first half when Shankland’s header struck the arm of Scales from close range, but he reversed his decision after studying footage.
That decision looked to spur Hearts on and Shankland forced saves from Kasper Schmeichel from long range either side of the interval.
Steven Naismith’s side survived a double scare just before the break when Gordon denied Furuhashi and Penrice made an excellent sliding block to deny Kuhn.
But the left-back was penalised for his next intervention and captain Callum McGregor persuaded Reo Hatate to hand the ball to Engels to send Gordon the wrong way from the spot.
Celtic struggled to build on the opener and Hearts came close when Blair Spittal’s cross set up fellow sub Musa Drammeh. Schmeichel got down well to save.
McCowan settled the home fans’ nerves with his first goal since joining from Dundee and Adam Idah was denied a goal in stoppage-time after VAR picked up an offside after he swept home Greg Taylor’s low cross.
Rodgers: A special day
Celtic manager Brendan Rodgers speaking to Sky Sports:
“All you can ask is that when we have a lot of players away on international duty that when they come back they show up.
“There’s no need to complicate it, just do what we’ve done many times and I thought the players did that really well.
“Give credit to Hearts because they came to defend and they make it difficult, they had good physicality.
“The longer it’s 0-0, it can give the opponents some confidence but we kept persevering, we get the penalty early in the second half and then we push on from there.
“It doesn’t really matter who scores, but I think Arne shows some really good composure with the penalty and it’s nice for him to get the feeling.
“It’s going to take some time for all the signings to mould into how we play and work, but he’s shown today he has that physicality and running power.
“For Luke, a real special moment. To score your first goal when you’re a Celtic supporter and to get that applause from all the crowd, it was a special day.”
Naismith: Neither were penalties!
Hearts head coach Steven Naismith speaking to Sky Sports:
“Small margins have been the difference I think.
“You’re playing against the best team in the country and I thought, first half, we were solid and frustrated them and in the couple of moments we got forward we could have done better.
“In my opinion, from what the directive has been, I’m not sure it is a penalty then in the second half I don’t think theirs is a penalty.
“I think the proximity of player to ball in both incidences, from what we’re seen in the summer, should have said neither were a penalty.
“It’s such a big moment in the game and when the game is stretched Celtic are always such a threat.
“The decisions have been made so I’m not going to say anything that’s controversial. The two of them are in the same ball park, if one is given then they both should be given and if they’re not they’re not.”