Nancy suffers nightmare debut as his Celtic challenge laid bare

An opportunity for instant impact or an immediate set back.

High stakes that backfired as Hearts left Glasgow with a three-point lead at the top of the table after their stunning 2-1 victory.

The timing of Wilfried Nancy's appointment as Celtic's new manager midweek had raised some questions, particularly given the run of results interim-manager Martin O'Neill enjoyed.

Level on points ahead of this top-of-the-table meeting with a game in hand. Some thought it prudent for O'Neill to see out this crucial week against Hearts, Roma and the Premier Sports cup final against St Mirren.

The argument was that change may disrupt momentum. It seemingly has.

Others put forward the idea that Nancy needed to get in, assess this squad ahead of the January window and implement his vision. He may have learned a lot in one game.

This was always going to be a big test of Celtic's recent progress and for the new man in charge in a baptism week full of big tests.

Little time to implement change but the chance to go clear in the league was there for the taking with a game in hand.

It was opportunity missed despite an opening that suggested Celtic had been reinvented immediately. In truth, aside from a bright start, few could argue at the outcome.

"The big talking point will be the change of formation," said former Celtic goalkeeper Pat Bonner.

"The first 20 minutes was maybe what he wanted, the speed, the counter-press, but you need to maintain that.

"When it comes to breaking down opponents in a compact area, they have been lacking for quite a while now."

A switch to a back three with Hyunjun Yang and Sebastian Tounekti deployed wide but well advanced. Benjamin Nygren and Reo Hatate slightly more central dropping into space.

It was a big ask for everything to click straight away. However, in the opening quarter, they looked rampant. The home crowd were loving the energy and intensity of their team and new manager.

He camped on the touchline throughout the first half. Time and again he urged them to go forward on the ball. No passing sideways, progress quickly either short or long.

Very promising and Hearts looked on the ropes. When Daizen Maeda got in he seemed certain to score. He didn't and, gradually, everything turned.

The first part is down to Hearts. They were wonderfully strong and gradually adapted. They got a grip of this and took control, even when in defensive mode. They deserve an incredible amount of praise and have firmly reminded everyone what a good side they are.

Maeda's miss was crucial. Derek McInnes said pre-match that he knew they would have to absorb pressure. They did and then punished their hosts.

For all Celtic's early swashbuckling, it absolutely evaporated. They lost the intensity. The bravery was gone.

Increasingly, they looked a little lost on such a big, big occasion, despite Kieran Tierney's injury time strike.

"This is not about the system," Nancy told BBC Scotland post match when quizzed on its impact.

"We started one way in the first half. And the second half, we kept going. Towards the end, it was not the same system.

"This is more about to check if we play with personality, to check what we can do better to unbalance the low block, what can we do better to avoid these two goals that we conceded."

It took until the final minutes for the home side to genuinely look like scoring. When they did, the game was lost, despite striking the crossbar shortly before their goal.

It would be unfair to level much criticism on Nancy this early. He did suggest he would look at nuanced changes in the short term. Perhaps he got a little too ambitious too early.

"They definitely need a striker and a winger on the right. After today the heads are down," added Bonner.

"You've got to break down opposition, you've got to move opposition. In that final third, Celtic were absolutely void of ideas.

"When they went two goals behind, it was gone. I just couldn't see them getting back into the game.

"Now Wilfried Nancy knows exactly some of the deficiencies that he has to work on. He's got to replace some players, he's got to get players in in the January window.

"They have a real fight on their hands to win this championship now."

After his first outing at Celtic Park, Nancy had experienced both sides of the crowd.

The early embers of his reign had fans off their seats. They were absolutely loving what they were seeing. It just lacked a goal.

Then almost everything was lacking as Hearts seized on their opportunity and the home support grew increasingly exasperated.

"I have many, many good things that I can show them [the players]," Nancy insisted.

"We need, obviously, to adjust on certain things but I was pleased with the mentality.

"I think that with more connection, with more relation, we're going to be able to do it like we did in the first half."

"We want to give emotion to the fans and they have the right to challenge us and to support us. I'm fine with that."