For 45 minutes the Great Escape juggernaut was gathering crucial momentum.
Just 45 minutes later it was brought to a shuddering halt.
Tyres slashed, petrol tank emptied and windows shattered, Pompey had indeed met a grisly end.
The big question remains whether Michael Appleton’s side can rally itself for the remaining six matches.
Sadly, for many supporters, the optimism has drained away.
Half a dozen matches left to dictate whether the Blues stay in the Championship.
Yet the damage may already have been done in one second half against Burnley.
Such is the precarious state of this relegation battle, even a below-par 45 minutes can be decisive.
And Pompey imploded spectacularly when faced with a crucial second period against the Clarets.
It was painful viewing, believe me, fingers firmly planted in front of the eyes.
After all their excellence against Hull and all the impressive work in the first half against Burnley, it descended into a Fratton Park car crash.
In recent matches Appleton’s men have lurched from the sublime to the ridiculous.
On Saturday they crammed that all into a single 90 minutes.
The subsequent 5-1 hammering left them further adrift from potential safety.
Just as crucial, belief among the fans has started to leak away.
You can hardly blame them after footballing sunshine was followed by a thunderstorm against Burnley.
Some had already hurried out of the exit before Charlie Austin completed his hat-trick.
Those who remained had to endure even more agony, the boos which greeted the final whistle delivering their withering verdict.
Pompey, at present, possess a knack of raising hopes of pulling off a sensational Great Escape.
Then, just as swiftly, casting doubts in the most cruel of fashions.
Just ask those who travelled to the Ricoh Arena little more than a week ago.
Just ask those in attendance on Saturday.
The 5-1 scoreline may have been rather more emphatic than perhaps Burnley deserved.
A win for the visitors was unquestionably deserved on the strength of their second-half performance alone.
But for the opening 45 minutes Pompey had been the better side, delivered more shots on goal and possessed the outstanding player in George Thorne. Granted, they had fallen behind to Kieran Trippier’s 16th-minute opener.
The response was swift, though, with David Norris sweeping home Luke Varney’s excellent cross.
From that moment on the hosts dictated play, albeit reliant on half-chance scraps to threaten the Clarets’ goal.
Varney and Chris Maguire buzzed, the defence were composed, Tal Ben Haim caused havoc down the right flank and Thorne was once again sensational.
The 19-year-old was head and shoulders above every player on the park during a dominant showing.
It was a Pompey display which echoed the second 45 minutes against Birmingham and the whole of the clash with Hull.
Then the match was truly turned on its head.
And with it, relegation now appears that much more realistic during these final few weeks of the campaign.
In Appleton’s eyes the decisive moment came 75 seconds into the second half. And it is hard to disagree.
Danny Ings’ goal not only restored the visitors’ lead but also set the tone for the remainder of the match.
David Edgar swung in a cross from the right and the former Bournemouth man rose to net.
With one header the belief was sucked out of Pompey as they crumpled alarmingly.
In that instant the match had been settled and those Blues fans present could only watch in bewilderment at the capitulation which unfolded.
The positive results elsewhere for the relegation rivals did little to lift such spirits.
With a trip to St Mary’s next on the horizon on Saturday, suddenly the doubts have become more audible.
Certainly the sight of Thorne leaving Fratton on crutches after injuring his ankle will not have helped boost morale.
Another blow on a day of setbacks for a group of supporters who have become familiar companions with disappointment.
To think matters started so encouragingly, regardless of Burnley breaking the deadlock through Trippier.
Chris McCann’s left-wing corner was dummied inside the box and the ball ran for the right-back to lash home the opener from distance.
Just three minutes later, though, Varney beat the offside trap to collect Thorne’s pass.
He drilled a cross in from the right which was rammed into the net by Norris – his seventh goal of the season.
Pompey began to control matters but remained restricted to half-chances rather than any clear-cut opportunities.
Then came Ings’ header 75 seconds after the break.
It wasn’t until the 74th minute when Charlie Austin would net his first.
A cross was drilled in from the left and the substitute appeared to handle before squeezing the ball past Jamie Ashdown.
With the match in stoppage-time, the former Poole Town striker – who was scoring goals in the premier division of the Wessex League less than three years ago – struck twice more.
Jason Pearce gifted Austin his second goal with a woefully underhit backpass intended for Ashdown.
The Clarets hitman intercepted and rounded the keeper before rolling the ball into an empty net.
The hat-trick was then completed with a high finish into the net after Pompey were hit on the counter-attack.
That added the gloss to a victory which Burnley thoroughly deserved for their second-half display alone.
The dejection was etched upon the faces of the players as they trudged off at the final whistle.
Realisation their abject second 45 minutes could be more costly than a mere defeat.
There are now six matches remaining to prolong their stay in the Championship – and one of those is at league leaders Southampton.
Of course, the fight is not done yet and Pompey fans will not allow their team to surrender.
But you can’t help feel that 45 minutes against Burnley could ultimately prove to be pivotal in the ending of the Great Escape.