The Swans Under-21's suffered a 2-1 defeat against Cardiff at Stebonheath Park on Tuesday.
Kristian O'Leary's men had a great chance to take a first-half lead when Connor Roberts was tripped in the box, but Rory Donnelly saw his spot-kick superbly saved by Elliot Parish.
However, the visitors took the lead shortly after the break as Jordon Mutch headed home and Rudy Gestede doubled their lead from the penalty spot after Kadeem Harris was brought down.
Swans midfielder Josh Sheehan curled home a superb effort from 20 yards late on, but it was too little too late for O'Leary's young side.
Swans Under-21's: David Cornell, Connor Roberts, Liam Shephard, Scott Tancock, Kurtis March, Lee Lucas, Josh Sheehan, Henry Jones (Alex Samuel, 71), Alex Bray (Luke Williams, 78), James Loveridge, Rory Donnelly.
Subs not used: Oliver Davies, Tom Atyeo, Sam Evans.