There were five teenagers in the Pompey side for their final Leasing.com Trophy group contest with Oxford.
And they were certainly not overawed in a 2-2 draw at the Kassam Stadium, followed by a penalty shoot-out triumph that secured a bonus point.
Bradley Lethbridge’s goal cancelled out Matty Taylor’s opener, with Anton Walkes giving the visitors a late lead before Rob Dickie grabbed a stoppage-time leveller.
With qualification for the second round already confirmed, the spot-kick success ensured top spot in Southern Group B and a home tie in the last 32.
And Joe Gallen was pleased with how the youthful Blues side fared against their more experienced opponents.
Pompey’s assistant manager said: “You just can’t beat us in this competition! It was a very good performance against what was a strong Oxford team.
“We had a lot of younger players in the side, so it was fantastic to get the points that mean we top the group and have a home game in the next round.
"Kenny’s got a history of developing young players at all the clubs he’s been at – we don’t want it to be any different here."
“The competition gives the club an opportunity to give those guys games and we can have a look at them against league opposition.
“Men’s football is totally different to playing for the youth team, but they all acquitted themselves extremely well.
“Kenny’s got a history of developing young players at all the clubs he’s been at – we don’t want it to be any different here.
“Supporters always love to see their own players coming through the system and we feel exactly the same.”
Alex Bass was Pompey’s star man, making a string of fine stops that included an excellent effort from Josh Ruffels in the shoot-out.
Gallen said: “Our keeper made some fantastic saves – which comes as absolutely no surprise to any of us.
“That’s what he’s there to do, but he made it look easy. He’s a very composed young man and we have no doubts about him.
“Overall, it was an entertaining game, but although this competition has it’s pluses, the most important thing is that we get a win on Saturday.”