Southampton's youngsters were forced to share the points on the road at Reading, after a late setback and a red card gave the home side a fortuitous route back in to the tie.
A dramatic last quarter saw Sam McQueen open the scoring from the penalty spot, before Armani Little was dismissed, and Ben House fired the hosts level minutes from the final whistle.
The visitors dominated proceedings from the off, and deservedly took the lead, but a chaotic final ten minutes culminated in a Reading equaliser, and a fatal blow for Saints' chances of victory.
In a first half characterised by a lack of clear cut chances, Little could - and perhaps should - have edged Saints in front on the stroke of half time.
Jake Hesketh whipped a corner to the back post, where the midfielder's late run was destined, but the pace on the delivery meant Little's connection was ineffective.
Returning from an eight month lay-off, Josh Sims played his part in the first 45 minutes, and looks to have shaken off an injury that has kept him sidelined since the back end of last season.
The 20-year-old was a threat down the right wing, linking consistently well with Hesketh, and was the architect of a breakaway chance in the 30th minute.
Sims drove the ball with purpose down the right, eating up the yards, before spotting the run of a tireless Michael Obafemi, whose three goal contribution had helped Southampton's Under-18s to FA Youth Cup victory just four days prior.
The striker couldn't untangle his feet, as the chance flashed by, but it served as encouraging indication that Sims' full return is forthcoming.
Matt Targett curled a free-kick a yard over the crossbar, but to no avail, while Reading's House hit the woodwork from range, before a goalless first half came to a close.
McQueen had the visitors straight on the front foot as the second period commenced, standing up a looping delivery to the far post, aimed at substitute Tyreke Johnson.
The winger's leap managed to control the lofted pass, but multiple onrushing defenders soon smothered the danger, before Callum Slattery rattled the post from a corner in the 55th minute.
Hesketh, the orchestrator of most attacking play, had his goalbound shot thwarted moments later, initiating a Reading break led by Ade Shokunbi. Some astute covering from Yan Valery dealt with the impending danger, as Saints continued to look defensively organised.
Growing in understanding and enterprise as the game continued, Hesketh fed the ball in to the path of Obafemi in the 65th minute, working another opening. The frontman's clever first touch fooled his opposition defender, engineering a change in direction, and gave Jonathan Afolabi the chance to shoot marginally wide.
The one way traffic was firmly dictated by the visitors and the deadlock was broken soon thereafter, courtesy of a confidently converted McQueen penalty. Afolabi was upended in the area, allowing the 22-year-old to fire Saints in to the lead.
But some late drama meant that a likely three points was soon reduced to one, as Little saw red and House levelled the scores in the 89th minute. The Royals' target man had looked dangerous throughout, and when presented with a rare chance to shoot from 10 yards, duly found the bottom corner of Jack Rose's net.
Line ups not available