Pompey Reserves began their Central League Cup campaign with a 5-2 defeat to Southend at Copnor Road.
It was a youthful side of academy players that featured in the first of three group stage fixtures, with the first team involved in League One action on the same day.
And the visitors broke the deadlock on 30 minutes when Norman Wabo curled home a shot from the edge of the box.
But the Blues were soon level, as Leon Maloney was brought down in the box and picked himself up to put away the spot-kick.
It was the Shrimpers who led at the break, however, as Matt Rush charged forward to head home Lewis Gard’s cross.
Alfie Stanley almost drew the hosts level again early in the second half, with the substitute smashing the ball against the crossbar.
Instead it was Southend that took control and Rush netted twice in quick succession to complete his hat-trick.
Stanley did raise hopes of a comeback when he found the target with 10 minutes of the match remaining.
But Charlie Kelman slotted home at the death to ensure it was the Essex visitors that claimed the points.
"We’re a young group and facing a full under-23 side, but the boys applied themselves fantastically well."
Academy manager Mark Kelly said: “We’re a young group and facing a full under-23 side, but the boys applied themselves fantastically well.
“There were some naïve mistakes that we brought on ourselves and that’s why the lads are little bit upset.
“We knew that in open play, we not only gave Southend a game, but also caused them quite a few problems.
“There have been a lot of minutes players recently, but that’s what we want. It was a brilliant game for them because they were up against some lads with real quality.”
Pompey: Boughton; Robb (Bruce 71), Mnoga, Dandy, Kelly (Bridgman 60); Johnston, Read, Whiting; Flint, Maloney (Stanley 46), Teggart