The youngsters suffered heavy defeat at Bolton on Saturday morning.
On a windy day in Lancashire, Saints disappointingly let an early lead slip as the hosts turned the game on its head and from there on never looked back, as they ran out convincing winners in the second game of the new season.
Jason Dodd's side took the lead on ten minutes through striker Tony GARROD, who scored for the second successive game with a well executed sidefoot finish after some clever control brought him the opportunity to strike at goal.
The Trotters hit back in the 18th minute, before taking the lead on 26 to put the visitors on the backfoot going into the interval.
Four minutes into the new half another sloppy goal from Saints' point of view saw Bolton edge further ahead soon after the re-start.
However, first year scholar and one of the better performers from the visitors, Joe CURTIS struck home on 55 with a fine left footed finish to bring Saints briefly back into the game at 3-2 down.
Just after the hour mark though, the Whites restored their two goal advantage before adding a fifth on 71 as Dodd's side chased the game to no avail.
Afterwards Dodd confessed it was a poor result, but there was plenty to take away from the performance.
"As a manger you find out a lot about your players when things don't go your way, so I think we'll take a lot from this game and the lads will take it as part of the learning curve," he said.
"We've conceded five goals, yet both sides have created seven or eight chances apiece, so to not take as many chances as them is disappointing.
"It was a poor performance overall though and it was our worst display from all of pre-season up until now, so it's back to the drawing board next week and work on some things, but also on the plus side, it's good to see Tony Garrod getting fitter and sharper in front of goal."
Saints Under-18s: Jack Dovey, Matt Young, Ben Martin, Lloyd Foot, Conor O'Sullivan (Luke Shaw 75), Lloyd Isgrove, Andy Robinson, James Ward-Prowse (Harrison Reed 75), Jordace Holder-Spooner (Callum Chambers 70), Joe Curtis, Tony Garrod.