If Martin O’Neill had any lingering doubts as to whether he should have stayed on as Celtic manager, this will surely have eliminated them.

The veteran boss took a few days to weigh up his future during the international break, presumably wondering whether he had the appetite for all this at the age of 74.

But he decided to remain, and a devastating 7-1 win against Hearts, still one of Celtic’s closest challengers, will have convinced him that he was right.

Let’s not pretend that everything is suddenly rosy at a club who are coming up woefully short in Europe and contriving to infuriate supporters with their incompetence off the pitch.

But a brutal demolition of the team who pushed them so close last season was exactly the kind of statement win O’Neill needed to invigorate his squad and maintain a semblance of unity in and around Parkhead.

One thing’s for sure: nobody will be complaining if there is more of this in the weeks ahead. Celtic were ruthless, but they were also hungry and relentless all over the pitch.

Some suggested later that it was reminiscent of the side under Ange Postecoglou, which will be music to the ears of Dermot Desmond as he seeks respite from the critics.

O’Neill, of course, is just as popular as the big Australian, but he has been searching for something this season, unsure as to the quality of his new signings and the best way to disguise his team’s faults.

Might he have stumbled on a winning formula? Prompted by successful substitutions made in the midweek defeat by Benfica, O’Neill made changes that worked a treat, most notably a first start for Callum Osmand.

Quick and direct, the young striker inspired Celtic’s breathless attack. Wide on the left is not his favoured position, but he was full of energy and ambition, certainly more than Sebastian Tounekti has offered in the same role.

Osmand, of course, was the player who completed the scoring on that momentous final day of last season when two late goals in a 3-1 win over Hearts earned Celtic a thrilling title triumph.

Here, his two goals in the space of two minutes underpinned a rampant first-half performance by Celtic. His first was a cool finish after calmly opening his body, his second a close-range header.

On the other side, Haissem Hassan was also given his chance. The Egyptian winger adds another dimension to Celtic’s attack, as he showed with one delightful spin away from his marker that resulted in a run and shot off the post.

Young Colby Donovan played his heart out at right-back, Kieran Tierney returned to his best and Camilo Duran showed his class when he peeled off Stephen Kingsley and curled in Celtic’s sixth. With the Colombia striker thriving at centre-forward, record signing Kasper Hogh can have no complaints about watching all this from the bench.

As ever, though, a degree of perspective is in order. If Celtic’s recent struggles in Europe are any guide, it will be a different story on Thursday night when Celta Vigo come calling. Dane Murray will be given a proper test at centre-half, Hassan will have to do some of the defending that he patently doesn’t fancy and the team as a whole will have to find a way of shoring up centre midfield.

What’s more, it would be a mistake to get carried away with this comprehensive dismantling of hopeless opponents. If Hearts’ intention was to go to Celtic Park and prove that they can challenge once again for the title, they failed in the most humiliating fashion. Rarely has a team purporting to be potential champions made such a feeble case.

It wasn’t so much that they were outclassed in every department (statistics, rather bizarrely, show that they had more possession and more attempts on goal than Celtic). It was that they lacked character. That they were physically and mentally weak. That they were hopelessly naive – as players in their individual duels and as a team.

Wouter Vrancken has been hailed for his work as head coach this season, but boy does he have some thinking to do – about his personnel, his tactics and how best to combine the two. This looked for all the world like a Hearts team who are not nearly as good as either they or their manager thought they were. A team and leader who had forgotten about the fundamentals.

In the first half of a ridiculously open game, it beggared belief how often Hearts’ players were left exposed at the back, victims of their casual team-mates and an over-optimistic game plan. They were half-hearted in the tackle, loose with the ball and, most worrying of all, unable to see the error of their ways. Not until they were 6-1 down did Vrancken pull off wingers Josh McPake and Calvin Miller. Never again will Celtic have it so easy against a so-called title rival.

Still, they are to be commended for taking full advantage with a barnstorming display that will boost everyone at Celtic Park. With Rangers only able to draw with Dundee on Saturday, O’Neill’s side are now four points clear of their city rivals.

They are also eight ahead of third-placed Hearts, although you wonder about the relevance of that statistic now. It may well be that this season’s title race extends into the final 11 minutes of the final game, but if it does, don’t expect the Edinburgh side to be involved.