Tayo Singerr netted twice as Pompey beat Luton 2-1 at the PMC Stadium in their final home fixture of the campaign.
He angled home the opener after good work from Michael Ani and Chinedu Agu out wide, only for Tate Xavier-Jones to level from the spot.
But the young Blues secured all three points when Singerr collected a Beau Mullins throw, spun and finished inside the keeper’s near post.
Lead professional development phase coach Sam Hudson said: “Our opponents were physical and quite direct at times, which we weren’t fully prepared for.
“They played a different style the last time we met, but I think that – like us – they had a few younger lads in.
“We went with two up front and that’s unusual for us – it was more a case of the personnel we had available and the other games we’ve got this week.
“But we started well and had the territorial advantage, with Tayo and Maxwell linking really well together.
"The final few minutes saw a bit of a barrage as Luton pushed players forward, but we won our duels and tackles, with Oscar making some saves."
“Our running stats were fantastic and we managed to attack well on the outside against their diamond.
“We gave the boys a bit of freedom and used our pace and power to cause Luton a few problems, with Tayo netting twice.
“The penalty we conceded was a harsh decision, but the lads reacted positively to that and we went back in front with a well taken finish.
“Tayo’s got the scoring touch at the moment, with different kinds of goals, and his clinical qualities are pleasing to see.
“We had a few 15-year-olds involved again and they performed well, so that’s another positive factor for us.
“The final few minutes saw a bit of a barrage as Luton pushed players forward, but we won our duels and tackles, with Oscar making some saves.
“It was a rounded performance, which sets us up nicely for our final league game at Plymouth on Tuesday and then the Portsmouth Cup quarter-final on Thursday.”
Pompey: Glover; Ani, Buckland (Sizer 46), Martin, Mullins (Hibbert 65); Agu (Thomas 81), Saunders, Staight, Osifo; Singerr, Hurst
