They sang ‘We are staying up’ before kick-off. They were right.
At 2.56pm, moments before the first of Pompey’s final three remaining matches kicked off, their League Two status was secured.
Caretaker boss Andy Awford had achieved safety – and in an improbable amount of time.
It had taken just four matches but the Blues had avoided relegation with games to spare, one of them yesterday’s fixture with Northampton.
For good measure, Pompey won that one as well – making it five successive victories under Awford to further enhance the belief he deserves the manager’s job on a permanent basis.
All manner of computations and calculations were conjured up in the build-up at Sixfields, centring on the outcome of the games involving Wycombe and Bristol Rovers.
In the end, another defeat for Rovers – this time 2-1 at home to Rochdale – kept it very simple as the Blues were mathematically safe before even kicking a ball.
Cue an away sell-out of 1,359 in celebration shortly before 3pm and a rendition of a song which has become a regular favourite under Awford’s reign.
As for the match, Danny East – marking a return to the club where he spent time on loan last season and his first appearance this year – netted the decisive goal.
He was one of eight changes in a transformed Blues line-up for what had so long been billed a crucial relegation encounter.
Retaining just three of those who started in the victory over Rovers on Saturday ensured there were plenty of eyebrows raised among the Pompey following.
Trevor Carson, Nicky Shorey and Jed Wallace were the only unaffected players as Awford rotated a side for a second game in three days.
Ben Chorley was excused following his wife giving birth this weekend, although with others from the previous match there were problems with knocks and niggles.
In came Daniel Alfei, Sonny Bradley, Joe Devera, Jake Jervis, Johnny Ertl, Wes Fogden, Patrick Agyemang and East to Awford’s first XI.
That meant six of those who started on Saturday joined Phil Smith on the bench, while Ryan Taylor and Jack Whatmough missed out completely.
Noticeably, there was no match-day 18 presence for Romain Padovani, Thery Racon, Yassin Moutaouakil and Ashley Harris, suggesting plenty about some of their futures at the club.
It took just six minutes for the Blues to break the deadlock – the goal stemming from an aerial foul on East down the right flank.
Alfei delivered a long ball into the box and there was East to rise high with his right foot to nudge it over Matt Duke and into the net for his maiden Pompey goal.
Northampton were reeling and in the visitors’ very next attack Leon McSweeney panicked to head the ball out for a corner when Jervis had closed any possibility of a backpass.
It was all Pompey at this stage and Jervis soon had appeals for a penalty having taken a tumble while trying to retrieve a mis-hit Shorey cross which looped high in the air.
The hosts were at their most threatening through the huge throws of Ben Tozer and on 28 minutes one from their left caused all sorts of problems before the referee spotted a foul on Bradley.
Emile Sinclair should have levelled moments later when Evan Horwood swung in a great cross from the left but the striker inexplicably pulled out of the header and the chance had gone.
Chris Wilder’s side began to improve and Chris Hackett curled one wide, while midfielder Ricky Ravenhill crashed a shot from long range out of the ground.
Then Carson produced a magnificent near-post stop to deny John Marquis in the 36th minute after the former Pompey striker had cleverly wrong-footed Alfei to create space.
The keeper pulled off another tremendous point-blank save to deny Darren Carter after bursting into the area, Alfei provided a crucial block to prevent the Cobblers netting the follow-up.
Northampton made two changes at half-time as they attempted to get back into the match, with Ian Morris and Ivan Toney replacing Sinclair and McSweeney.
Toney almost made an instant impression but steered a header straight at Carson after a corner from the hosts had caused problems.
The striker then entered the referee’s notebook following an ugly lunge on fellow substitute Danny Hollands – the Pompey man left writhing in agony from the foul which could well have warranted a sending off.
Both sides were struggling to create, although Mathias Kouo-Doumbe almost netted with a spectacular flying kick on 65 minutes after Marquis had flicked on a corner.
In their next move, the Cobblers’ Hackett pulled the ball back from the right-hand byline to find Toney but the young striker hit his shot into the ground and it bounced over.
Still the pressure continued and Bradley’s weak header back was latched upon by Marquis whose lob was finger-tipped out by Carson.
The visitors were clinging to their lead but on 85 minutes came close to sealing it only for Duke to come out and smartly block at Wallace’s feet.
It mattered little as Pompey saw out the victory on the day they had earlier secured their Football League safety.