Kal Naismith was the spark who ignited the improbable surge to the League Two title.
Yesterday he initiated potentially a breakneck season finale once more as the Blues basked in a first home win of 2018.
It seems ludicrous to suggest the League One play-offs are within Pompey sights following two months and 26 days without a Fratton Park triumph.
Yet that is precisely the scenario, with a 3-0 victory over Oxford United putting them within two points of the top six.
Naismith, the player with eight games remaining on his existing deal and facing an uncertain future, marked only his 12th start of the campaign with an early opener.
Granted, the hosts creaked following an excellent start, the U’s under new management in the form of Karl Robinson striking the bar and having a shot cleared off the line by Brett Pitman.
Then arrived a key moment in proceedings with the awarding of a penalty on 60 minutes following Matt Clarke’s foul on Rob Dickie.
Alex Mowatt hit the inside of the post, then struck the gloating Nathan Thompson with a left hook as Oxford were suddenly reduced to 10-men.
It was left to Pitman to tap home two excellent Jamal Lowe crosses from the right, taking his season’s tally to 19 in all competitions.
An excellent afternoon in the absence of Kenny Jackett, the manager not present following a family health issue, with assistant boss Joe Gallen instead taking the reins.
And, following successive wins and consecutive clean sheets, suddenly the Blues have broken into a run with eight matches remaining in the chase to earn an unlikely play-off position.
The team lined-up with Thompson earning an instant recall after missing the Blues’ past four matches following a sending off at Southend, his second red card of the season.
He came straight into midfield, with Dion Donohue dropping back into his left-back role.
That meant Brandon Haunstrup moving to the bench, representing the only change to the team which last weekend won at Oldham.
Elsewhere, fit-again Gareth Evans joined Haunstrup on the bench, back in the squad following four matches sidelined with a hamstring problem.
Meanwhile, Jack Whatmough continued to be preferred to Christian Burgess alongside Clarke in the centre of defence.
Opponents Oxford included ex-Pompey players Wes Thomas and Simon Eastwood in their starting XI, the first of Robinson’s era.
Leading-scorer Thomas headed into the match with 10 goals, yet without a League One strike since New Year’s Day.
When play got underway, it took just five minutes to break the deadlock – in Pompey’s favour.
Donohue won the game’s first corner, delivering it himself from the left, for it to be met at the far post by the head of Clarke, sending the ball back across goal.
There was turned home by Naismith from close range to hand the hosts the lead, while registering his third goal of the campaign.
Moments later, Connor Ronan crossed from the left and Naismith attempted to flick the ball with his head, only to send it wide of the far post.
Ryan Ledson earned the game’s first booking when, on 13 minutes, he crashed into a tackle of Ronan, which was suitably punished.
The Blues were on top and when Naismith whipped in a ball from the left-hand touchline, Ashley Smith-Brown almost slashed his clearance into his net, instead conceding a corner.
There was a scare, however, on 21 minutes when James Henry struck Pompey’s bar.
The ball came from right and the in-form midfielder pounced on the edge of the box with a fierce right-footed shot which bounced off the woodwork and was cleared behind.
It was proving an entertaining affair and when Lowe drove in a cross from the right, Pitman was agonising short with his lunge, although afterwards appealed for a penalty for tugging back.
On 27 minutes, there were appeals for a Pompey penalty as Pitman tumbled under a challenge from Dickie while chasing Anton Walkes’ precise ball over the top.
Referee Charles Breakspear consulted his assistant to award a free-kick just outside the box, while handing a yellow card to Oxford’s defender.
At the other, a lovely spin and turn on 32 minutes from Malachi Napa produced a curling right-foot shot which appeared to be heading for the far corner, only for Luke McGee to fingertip it around the post.
From the resulting corner, McGee initially parried a goal attempt before Dickie’s header was cleared off the line by Pitman.
The U’s had increased their attacking threat and Dickie then powered a corner from the left just past the far post with a header as the hosts began to creak.
Thompson became the first Pompey player to enter the book after bundling over Henry as he attempted to end a swifty visiting counter-attack.
The game resumed for the second half with Naismith quickly earning a booking following a slide challenge which turned into a trip on Henry.
On 51 minutes, Gallen made his first substitution, with Evans introduced for Ronan, occupying a central-midfield role in the process.
The match exploded on 60 minutes, following the awarding of an Oxford penalty.
Clarke was adjudged to have brought down Dickie during the flag-kick delivery from the right, with Mowatt stepping up for spot-kick duties.
Yet the midfielder’s left-footed shot cannoned off the inside of the left-hand post, bouncing to safety, with Thompson quick to confront him with some chosen words.
Mowatt lashed out into the face of the Pompey player, sending him to the floor, sparking a penalty-box ruck, with McGee leading the anger towards the penalty taker.
Following a delay, McGee was booked, while Mowatt has dismissed for his actions – and from the 63rd minute Oxford were down to 10-men.
Pompey now had the numerical advantage and doubled their lead on 69 minutes following a wonderful cross from Lowe.
Delivered from the right with precision, it was crying out to be tapped in at the far post, with Pitman obliging, hammering it into the roof of the net.
The hosts were sensing more goals and Pitman almost grabbed himself another when his right-footed shot deflected off John Mousinho, sending the keeper the wrong way but agonisingly wide of the far post.
It was 3-0 on 79 minutes when Thompson put Lowe clean through, taking the ball past the keeper before crowded out as he attempted to shoot into the empty net.
However, the winger managed to dig out a cross for Pitman to tap home his 19th of the campaign.
There was no coming back for Oxford, as renditions of ‘We’re On Our Way’ emerged from the Fratton End.
Perhaps Pompey really are – again.