Pompey will be playing in League Two next season as their promotion hopes were sickingly dashed in stoppage-time at Plymouth.
Peter Hartley’s late, late winner gave the Pilgrims a 1-0 victory to send them to Wembley at Home Park.
Hartley struck with a header which ricocheted off Enda Stevens to deliver heartbreak for the Blues.
It means Paul Cook’s side face a fourth season in the basement tier of English football.
And it couldn’t have happened in more gut-wrenching fashion, with the fatal blow delivered at the death.
Plymouth were asking the questions late on after a cagey affair.
Jamille Matt had decent second-half chances and former Pompey man Jake Jervis headed against the post.
But then came Hartley’s intervention to spark at pitch invasion after the final whistle arrived moments later.
After the breathless first leg, the opening 45 minutes at Home Park proved a more tense clash.
Graham Carey’s 25-yarder was well saved by Ryan Allsop after two minutes.
Pompey’s reply was to see Kyle Bennett fire a 20-yard effort just wide after 11 minutes.
Graham Carey’s free-kick and Marc McNulty’s long-range drive were then both off target in a tight encounter.
Pompey were then forced into two changes as Gareth Evans limped off after being clattered by Carl McHugh.
Danny Hollands followed him down the tunnel after an awkward fall, with Adam McGurk and Fratton teenager Ben Close coming on.
McGurk so nearly got in from Gary Roberts’ through ball after 36 minutes but Luke McCormick gathered.
Bennett and Jervis were both off target with chances at the end of the half with little in it.
Pompey started the second half brightly, with Roberts and McGurk having early chances.
Ben Davies then fired a 25-yard free-kick into the side-netting after Curtis Nelson fouled Roberts.
Roberts then had a decent chance after McCormick topped his clearance, but couldn’t get his 25-yard effort on target, with the Plymouth keeper out of his goal.
Danger man Matt then failed to make the most of two clear chances for Plymouth as they upped the ante.
First Michael Doyle and McNulty lost the ball with sloppy play, allowing Matt to step aside Christian Burgess’ challenge - but fire wide when in space.
He then headed wide from Carey’s corner as Plymouth asked the questions.
Pompey were indebted to McNulty after 74 minutes after he cleared off the line as a corner bounced goalwards off Adam Barton.
It was looking increasingly like extra-time would be needed to separate the sides.
Close volleyed wide from a corner with six minutes remaining.
And there was heart-stopping moment in the 89th minute as former Pompey man Jervis headed off the post from Craig Tanner’s cross.
Allsop saved another header from Matt, but then came the decisive moment as Hartley bundled his header home.
There was no time for a reply and the pain of the late goal means play-off heartache arrives again for the Blues.