An extra-time defeat to Leicester saw Pompey Academy exit the FA Youth Cup at Fratton Park.
They were under the cosh in the early stages, but grew stronger as the first half progressed and Dan Smith fired them ahead from the spot.
But Kairo Edwards-John levelled early in the second half and the young Blues were not able to make the most of the numerous chances they created.
The Foxes took advantage, as Edwards-John netted again to book the visitors a place in the fourth round.
It was Leicester who began to dominate following a cagey start to proceedings and they carved open a number of chances.
A fine save from Jack Collins stopped them breaking the deadlock on seven minutes, with the keeper denying Simran Thandi from point-blank range.
He also prevented Edwards-John from finding the net from an acute angle, while a Conor Tee free-kick flew narrowly wide.
And it looked like the hosts were going to be in for a tough night, as Collins tipped Tyrese Shade’s effort over the bar.
The Foxes went even closer from the resulting corner, with Harry Kavanagh well placed to clear from the line.
Pompey finally carved out an opening at the other end on 19 minutes, although an impressive challenge from Calvin Ughelumba stopped Matt Mayes from getting a shot away.
The tie settled down after that early flurry, although it was still the visitors looking more likely to open the scoring.
So the Blues could not waste an excellent opportunity of their own, as referee Adam Penwell spotted a foul on Mayes by Lukas Husek.
SMITH was up to the challenge, however, confidently sending Rhys Davies the wrong way from the spot.
And that was the way it stayed up until the interval, as Leicester failed to find a way through the home defence.
Half Time: Pompey 1 Leicester 0
But the Foxes made a blistering start to the second half, as the ball was worked into the box, where Edwards-John was waiting to slam home.
Pompey tried to hit back immediately and almost restored their lead when Smith bent a shot just past the post.
Both sides were showing plenty of ambition in the hunt for a winner, as the action switched from one end to the other, albeit with a clinical edge lacking in the final third.
The hosts did show plenty of persistence to hand Smith another chance, although he failed to find the target from the edge of the box.
Bradley Lethbridge then had an effort that appeared to be heading for the target until Thandi got in the way to divert the ball behind.
The same player also tried his luck on 77 minutes, only to fire wide after being teed-up in the box by Freddie Read.
But Leicester soon had an opportunity of their own, with Collins getting down to his left to palm clear Tee’s free-kick.
And Collins then denied the same player again in stoppage-time to ensure the tie would go to extra-time.
After 90 Minutes: Pompey 1 Leicester 1
Both teams were visibly tiring as the action became more frantic, but a moment of quality for the visitors saw them take the lead for the first time.
It was a second goal of the evening for Edwards-John, who cut inside from the left before rifling a shot into the opposite corner.
Pompey tried their hardest to get back in the contest, but Leicester were content to soak up pressure and looked dangerous on the break.
And the Blues were unable to find a goal to take the tie to penalties, as their FA Youth Cup adventure came to an end.
Pompey (4-2-3-1): Collins; Kavanagh (Mnoga 100), Casey, Dandy, Hancott; Brooks, Read; Smith, Maloney, Lethbridge (Johnston 104); Mayes (c)
Goals: Smith 32 (pen)
Subs not used: Pitman, Flint, Whiting
Leicester (4-2-3-1): Davies; Thandi, Ughelumba, Husek, Thomas; Leshabela (c), McLeod (Gill 78); Williams (Brown 66), Tee, Edwards-John (Meite 106); Shade
Goals: Edwards-John 47, 99
Subs not used: Storcyzk, Elewa-Ikpakwu
Referee: Adam Penwell
Attendance: 603