Pompey produced a disappointing performance in their 3-0 defeat to Arsenal at London Colney.
Early goals from Alban Bunjaku and Phil Roberts meant the Blues were always chasing the game.
And Calum Webb’s strike on 75 minutes completed a comfortable victory for Steve Bould’s young Gunners.
Director of youth operations Paul Smalley said: “The players had a positive week and have been working hard on their development, so the result was disappointing.
“For some reason they appeared intimidated and fearful even before the game began and this was reflected in their performance.
“We only performed to the standard we expect for a 25-minute spell in the second half, although Raphael Duyile – our trialist from Bolton – gave a good account of himself.
“We showed little resolve and passion and that was a bitter disappointment – but hopefully the players can learn from this experience.”
Pompey: Gledhill; Tallack, Bennett (Wheeler 25), Magri, Grant; Higgins, Stockford (c) (Vine 46); Duyile (Seeley 81), Harris, Butler; Walshe
Subs not used: Tsovolos, Colson
Arsenal: McDermott; Wynter, Angha, Monteiro, Bihmoutine (Smith 82); Monakana (Rees 82), Webb (Edge 82), Ebecilo, Neita; Roberts, Bunjaku
Sub not used: Cook