If, as seems ever more likely, Inverness are to be relegated this season no opponent will bear more responsibility than Liam Boyce who scored all four goals last night to take his tally in derbies this season to nine and his team a massive step closer to Premiership safety.

A fair few in their own ranks carry their share of blame for their plight, though, most conspicuously this time Ryan Esson who, having responded to a late season injury emergency to be part of the team that made history for his club in the 2015 Scottish Cup final, bruised that legacy with the pivotal error transformed the nature of a previously competitive encounter.

That said, plenty of others could share with the stand-in goal-keeper - playing just his third match since that day at Hampden after sitting out the whole of the following season – responsibility for the way they capitulated thereafter.

Even setting aside the locals’ fabled perfect pronunciation any talk of ‘doon derbies’ would have been out of place at the Global Energy Stadium ahead of this encounter but the Highland neighbours knew this was a match that could have a telling impact on their respective prospects of avoiding going down from the Premiership.

An extra touch of tension was added to proceedings, with referee Craig Thomson among those caught in traffic following an accident which deprived a Porsche of a rear wheel just north of the Kessock Bridge, its condition representing a pretty decent metaphor for the way things have gone for those departing Inverness on away match days and nights this season.

This first match after the split could have been the ideal time to right the vehicle and turn the course of this campaign around for Thistle, their only problem being that, for all that their hosts’ manager Jim McIntyre had spoken in advance about the importance of having a Highland derby in the top flight, his own team’s situation was sufficiently precarious that they could not afford to show any sort of generosity.

The game’s first opportunity, an excellent one at that, fell to Inverness when Alex Fisher should have reacted better, almost seeming to be taken by surprise as, from Iain Vigurs’ corner on the right, the ball reached his feet at the far post, just three or four yards from goal.

The impression that the hold-up on the way to the ground had done little for Mr Thomson’s patience was meanwhile reinforced when, perhaps rather harshly, he reached for a card his yellow card after Jim O’Brien dived into a challenge on David Raven as the surface was lubricated by a chilly shower of rain. That said the repeated apologies from O’Brien acknowledged awareness that he had been a bit rash.

A lively pace was being maintained and County properly threatened for the first time when Michael Gardyne’s teasing cross allowed Liam Boyce to put pressure on Esson. In the end neither made effective contact and the ball fell clear.

Esson’s lack of match practise was then critically exposed, costing his side the opening goal in 21 minutes. Craig Curran had done well to keep the ball in play but Jamie McCart seemed to have things under control as he returned the ball to his goal-keeper. It was perhaps slightly short of pace, but the bigger issue was the heaviness of Esson’s touch, allowing Boyce to nick the ball away from him and ram the ball home left-footed.

It had been an even contest to that point, with the visitors looking at least as sharp as the home side, but the impact on the mood of both sides was clear and if not inevitable it was by no means a shock when the lead was doubled. David Raven was the main culprit this time as he had the ball stolen from him by O’Brien and his cross from the left was met at the near post by the head of Boyce who deftly lifted it over Esson who had no chance this time.

Growing frustration among the Inverness contingent was demonstrated on and off the field towards the end of the half as, following a sustained chant of ‘sack the board,’ a blue flare was thrown onto the pitch in front of the visiting support just as Liam Polworth, after taking a tumble when challenged by Marcus Fraser as he carried the ball into the box, had an angry exchange with Tim Chow who felt he had gone to ground too easily.

If Inverness felt aggrieved at not getting the award there was more of a sense of despair when, four minutes into the second period, before half-time substitute Billy McKay had any chance to make an impact, they conceded a penalty in a near identical position, Raven bundling over Martin Woods.

Boyce, if course, stepped forward and, right-footed, tucked the ball confidently inside Esson’s right post, with the goal-keeper heading in the opposite direction.

If things were not grim enough, they found themselves 4-0 behind and down to 10 men with half an hour remaining when Liam Polworth was red carded for conceding a second penalty.

Ryan Dow’s touch, bringing the ball down and across his opponent with a single touch left the midfielder only one option to prevent him bearing down on goal and, in turn, Mr Thomson none whatsoever as he meted out the double punishment. Boyce then took on the executioner’s duties, one final time, driving the ball the same way as he had with the previous penalty.

Esson guessed correctly this time, but it was struck too well and the striker departed soon after to the warmest of receptions.