Pompey Academy finished the season with a 4-1 defeat to Southend at Copnor Road.
It was a day of celebration for the visitors, with the result seeing them clinch the Merit League One title.
The Blues, meanwhile, ended up just one point short of finishing in the top half of the 12-team division.
Goals from Freddy Eastwood and Charlie Kelman saw Southend race into a commanding lead by the midway point of the first half.
Pompey reduced the deficit when Leon Maloney chipped the ball towards the back post, where Josh Flint (pictured) headed home.
But the Shrimpers almost immediately restored their two-goal lead, as Matt Rush converted Eastwood’s centre.
And Eastwood wrapped things up after the break, finishing from close range after a free-kick had been parried away.
Academy manager Mark Kelly said: “It was a last get-together for our second years and their final game as a group before a few of them depart the club.
"Both sides had opportunities and they were just more clinical."
“We actually started brightly and despite falling behind, had a lot of possession and a few chances in the first half.
“But we took too many long shots instead of getting the ball nearer the goal to cause Southend problems.
“Josh’s header got us back into it and then we became more expansive, chasing a route back into the game and allowing our opponents to take control.
“I’m not saying that 4-1 was a fair reflection of what happened on the pitch, but they deserved their win.
“Both sides had opportunities and they were just more clinical. They took their chances well and we congratulate them on securing the title.”
Pompey: Durin (Pitman 76); Kavanagh, Bruce (Dandy 72), Mnoga, Hancott; Read, Whiting (Bridgman 63); Johnston (Stanley 72), Maloney, Flint; Lethbridge