A perfect penalty from debutant Kelechi Iheanacho secured three points for Celtic at the end of a pulsating Scottish Premiership encounter with Kilmarnock.

The VAR-awarded spot-kick had Celtic fans in the Chadwick Stand, half of whom had delayed their arrival until the 12th minute in protest at the club's board, celebrating wildly as their side returned to the top of the table.

In contrast, the home support were crestfallen after being on course for at least a point.

David Watson had powerfully nodded in to cancel out a fine diving header from Daizen Maeda, the off-form Japan star stooping to direct in Marcelo Saracchi's fine cross shortly after half-time for his first league goal this season.

But there was to be a dramatic end as referee John Beaton went to the monitor after James Forrest's shot struck Lewis Mayo's arm on its way, with the Kilmarnock defender judged to have had his arm in an unnatural position.

Around half the visiting support delayed their entry at Rugby Park in protest against what they view as a lack of ambition and spending by Celtic's hierarchy.

Chants of 'sack the board' after the final whistle were somewhat muted, given the joy that greeted Iheanacho's late strike.

Until the first goal went in, a fairly drab, gloomy affair ensued, illuminated every now and again by the skill, speed and flair of Celtic wing debutant, Sebastian Tounekti, who already looks like the best bit of business in a transfer window that otherwise frustrated manager Brendan Rodgers and the support alike.

Celtic look like they needed something to spark them into life this season, and it may well just have been provided by Iheanacho's dramatic introduction into Scotland's top flight, the Nigeria international having joined as a free agent after the closure of the summer transfer window.

Though disappointed, Kilmarnock will take great heart from the way they contained the visitors for much of the match and the threat they posed towards the end of the game.

Celtic lead Hearts on goal difference after five games, with Hibernian and St Mirren both seven points off the top two. Stuart Kettlewell's Killie, eighth, remain on four points.

It looked as though Maeda's return to scoring form would get Celtic over the line, despite another unconvincing display, but an inability to kill of their stubborn opponents nearly came back to bite the champions before a contentious late penalty and Iheanacho's fine conversion of it.

Until Maeda scored, it had been a familiar tale for the visitors - plenty of the ball, precious little danger of them doing much with it. Lots of recycling of the ball from one side of the field to the other. Plenty of touches from the midfield trio and the back four. Serious penetration? Not likely, unless new Tunisian winger Tounekti was on the ball.

He was the one player in hoops who looked like he could create something, or at least eliminate his marker and produce a moment of quality. Few of his team-mates appeared capable of similar.

From a side bursting with creativity and goals last season, it's quite the drop-off in quality. Sadly from their perspective, it's not particularly surprising given the lethargy that has blighted much of the early stages of this campaign.

For Kilmarnock, it was a bitter pill to swallow. They very nearly had another precious point and no-one in the stadium would have begrudged them it. The ongoing project under new boss Kettlewell continues to gather momentum.

Disciplined, well organised, willing to work. All part of his 'non-negotiables' but nonetheless impressive when seen put into action against a side who've just spent the bulk of £10m on two new wingers, one of whom, Michel-Ange Balikwisha, was made to look completely anonymous.

In the end, Killie might feel this is the one that got away. They were the side with all the late pressure after Watson's equaliser and they had Celtic hanging on in the end before the late twist to this tale.

Kilmarnock manager Stuart Kettlewell: "Frustration, disappointed. Gutted for the players, not for myself. To lose it in that nature is heart-breaking for them, sore one for us all. We looked like the team that would go on and win it. Players executed the game plan really well through stages.

"I sat here with the players and staff for a referee's meeting. That type of incident was addressed. We were under the impression that wasn't going to be given as a penalty any more. If that's not the case or the rule, someone will have to tell me."

Celtic manager Brendan Rodgers: "In the Celtic spirit, we kept going right to the end and I'm delighted for Kelechi Iheanacho to get the penalty. I know he thrives off confidence from his team-mates, manager and supporters.

"Delighted for the team, there's been so much noise, but we got out there and won. It's still very early in the season. We've started well in the league with our four wins and a draw and we're only going to get better."

Celtic continue the defence of the Premier Sports Cup next weekend with an away tie against Championship Partick Thistle on Sunday (15:30 BST).

Kilmarnock play their quarter-final tie at home to St Mirren on Friday (19:45).