Pompey Academy conceded deep into stoppage-time as they were forced to settle for a Merit League point at AFC Wimbledon.
There were 89 minutes on the clock when they took the lead, as Oscar Johnston (pictured) converted a pass from substitute Charlie Bell.
But a long throw then caused problems in the Blues box and Ayoub Assal took advantage to find the net off the underside of the bar.
Academy manager Mark Kelly said: “It was a typical game against a Wimbledon side who were big and solid.
“They looked to put us under pressure with long balls, but we got it down and were able to move into good areas.
"There were chances for us to finish them off, but at 1-0 anything can happen."
“We should probably have had a couple of goals in the first half, with Alfie Stanley going closest, while we were solid at the other end of the pitch.
“After the break we continued to move the ball around quickly and Stan Bridgman headed over from close range.
“We were driving into their box to create some decent openings and the lads also looked solid to deal with Wimbledon’s threat.
“The ball broke for Charlie late in the game and Oscar got across his marker to send a shot into the bottom corner.
“They continued to pump the ball into our area, but we looked comfortable until virtually the last kick of the game.
“We didn’t deal with the long throw and the ball bounced around our box until their lad put it into the net.
“It was a difficult day overall against a side who played the way they did and we should have shown better concentration levels to see things out.
“There were chances for us to finish them off, but at 1-0 anything can happen. The lads were gutted and should have been more clinical, so it was a bit of an education for them.”
Pompey: Durin; Bruce, Mnoga, Robb, Hancott; Whiting, Read; Johnston, Bridgman, Teggart (Bell 56); Stanley
Subs not used: Rew, Lee