Pompey exited the Hampshire Cup after losing on penalties to Folland Sports at the Arrow Arena.
They controlled possession throughout the contest, but were unable to convert that into many meaningful chances.
Their Wessex League Division One opponents took the lead through Fabio Manuel after the break, but Harry Clout (pictured) came off the bench to net a last-gasp leveller.
It was not enough to book a quarter-final berth, however, as the hosts won the resulting shoot-out to progress.
There were no senior professionals on display for the Blues, whose entire side was made up of academy players.
It was Folland who had the first chance to break the deadlock following a defensive mix-up, but Ryan Long could not lift the ball over a back-pedalling Oscar Glover.
The Planemakers also won a series of corners as they looked to put their opponents under some early pressure.
But the Blues began to see more of the ball as the first half progressed and were trying to pass the ball around on a difficult surface.
They were dominating possession and looking to push Folland back, but could not find a route through to test Konrad Szyszko.
There was a nervy moment at the other end when Kevin Bosaka’s back-pass caught a bobble and Glover did just enough to prevent Long from opening the scoring.
Most of the action was talking place in the hosts’ half, though, and they were doing a good job of denying Pompey any shots.
There were plenty of entries into the final third, with the ball just not landing for a blue-shirted player.
And when Connor May did manage to cut it back into the mixer, a defender was on hand to hack the ball over his own bar.
Half Time: Folland Sports 0 Pompey 0
Pompey started the second half as they had ended the first and soon set about looking to attack their hosts.
They had an early opportunity when Beau Mullins escaped down the left and sent in a dangerous low delivery that Szyszko just about managed to gather.
Mitch Aston then played a superb cross-field pass to Brian Quarm, whose attempted ball into the box was cut out by Dan Page.
They were starting to look more dangerous and Maxwell Hurst tested Szyszko’s handling after May had been tackled inside the area.
The Blues still had to be alert at the other end, though, and Jack Fox made a fine sliding challenge to prevent Long converting a low Manuel centre.
But it was the visitors looking more likely to break the deadlock and when Folland struggled to deal with a Mullins corner, Hurst flicked the ball against the top of the crossbar.
They fell behind on 71 minutes, however, as a long throw found Manuel, who spun and sent a sharp shot into the bottom corner.
Then, just moments after Mullins had been denied a penalty after appearing to be shoved to the turf, Folland broke and Manuel drew a smart stop from Glover.
And despite battling away during the closing stages, it looked as through Folland would be able to hold on.
In stoppage-time, however, substitute CLOUT sent in a cross-shot from wide on the left that somehow went over Szyszko and found the net.
After 90 Minutes: Folland Sports 1 Pompey 1
May stepped up first for the Blues and saw his effort saved by Szysko, with Aston, Clout, Luke Staight and Jack Fox all finding the target.
Bastian Smith had come on between the sticks for the shoot-out, but Folland were clinical and converted all five of their penalties to go through.
Folland Sports (4-2-3-1): Szyszko; Hinton, Matonga (c), Page, Andries; Austin, Taylor (Gatera 70); Nyakumbi (Ball 81), Marcinkowski, Manuel; Long (Palmier 90)
Goals: Manuel 71
Subs not used: Haylor, De Rosa
Pompey (4-1-2-1-2): Glover (Smith 90+6); Quarm, Bosaka (Howard 46), Fox (c), Mullins; Aston; Murray, Staight; Keteku (Clout 71); Hurst, May
Goals: Clout 90+2
Subs not used: Ayres, Buckland
Referee: Oscar Whiting