Pompey Academy suffered late heartbreak after Southend United snatched an injury-time winner in their EFL Youth Alliance Merit League One fixture.
The Blues’ under-18 side looked destined to return home from the Shrimpers’ Boots and Laces training ground with a share of the points.
However, Matt Rush’s stoppage-time strike for the hosts past visiting keeper Leon Pitman proved decisive, handing Southend a 3-2 victory.
In a thrilling game, Pompey took the lead on 18 minutes through Bradley Lethbridge.
Fresh from his hat-trick in last week’s dramatic 4-3 victory over Bristol Rovers, the striker made the most of Dan Smith’s perseverance in the home penalty area to calmly fire past keeper Harry Seaden.
Southend responded on 38 minutes when Terrell Egbri pressed high up the pitch and won the ball off Pitman before stroking the ball home.
The hosts took the lead three minutes into the second half.
A corner from Jon Benton found Taylor Curran in the Pompey box and he headed home from close range.
The Blues thought they had salvaged something from the match when Stan Bridgeman scored from close range after Smith’s free-kick smacked against the post.
But there was sill time for a winner – and it was the Shrimpers who got it after Rush was perfectly set up by Sewa Marah on 91 minutes.