Pompey Academy had to settle for a 1-1 draw at Forest Green after playing much of the second half with just 10 men.
The Youth Alliance League contest came just three days after the Blues had romped to a 6-0 victory over the same opponents on home soil.
And it looked like another win was on the cards when Harrison Brook (pictured) fired the visitors in front just before the hour mark.
Eoin Teggart then appeared to have doubled the lead, only for his celebrations to be cut short by an offside flag.
But the Blues soon saw defender Haji Mnoga sent off for picking up his second yellow card of the afternoon.
And Forest Green made their numerical advantage count, as Luke Hallett sent a header looping into the net.
Academy manager Mark Kelly said: “The game had a good flow to it and it looked like we had a grip on things after taking the lead.
“Harrison combined well with Alfie Stanley on the edge of the box and hit a great effort right into the top corner.
“It was then a tight offside call that denied Eoin, who also saw a shot kept out by a superb save from their keeper.
"We weren’t able to capitalise on those opportunities, but I was pleased with the overall performance of the boys."
“We seemed comfortable and probably should have had more goals because there were some excellent deliveries into the box.
“The action was going back and forth, but we were still in control and got into some really dangerous positions.
“But the sending off was a turning point. The first booking was actually an excellent tackle, but you’ve got to be a bit cuter when you’re on a yellow card.
“He slid in for a tackle when he should have stayed on his feet. It’s a lesson for Haji about discipline and something he’ll learn from.
“Forest Green then took more risks to get back into the game, but we were resilient and dealt with balls into their box.
“Unfortunately, they managed to level with what, to be fair, was a really good header, although we still created chances with 10 men.
“We weren’t able to capitalise on those opportunities, but I was pleased with the overall performance of the boys.
“I’ve been impressed with the way their defending has improved over the past week and they’re showing the right mindset.”
Pompey: Seymour; Kavanagh (c), Bruce, Robb, Mnoga; Bridgman, Bell; Teggart, Lee (Kelly 63), Brook; Stanley (Anderson 66)