Swansea City Under-18s fell to defeat in the opening game of their Professional Development League campaign as they conceded a late winner at Barnsley.
The Swans were on course for a draw until Barnsley substitute Emmaisa Nzondo put the home side back in front four minutes from time.
The Tykes had taken an 11th minute lead through Josiah Dyer’s header, but Iwan Morgan put the Swans back on level terms in the 73rd minute from a Kyrell Wilson cross, while the visitors were also unable to convert a first-half penalty.
The hosts started brightly and they took the lead when Dyer was on hand to nod home from a pinpoint cross.
The Swans went close to levelling on numerous occasions as Morgan and Wilson were denied by Rogan Ravenhill in the Barnsley goal.
Another chance to level came just after the half-hour mark as Swansea were awarded a penalty as Josh McKay committed a foul in the box.
But Ravenhill made a fine stop to deny Josh Carey’s spot-kick as he clawed the ball away to ensure the home side remained ahead at the break.
Early in the second half Barnsley went close to extending their lead as Milan Benjamin's low driven shot just went wide.
But minutes later the Swans got on the scoresheet thanks to Morgan, who was on hand to divert the ball into the net from Wilson’s cross.
However, it wasn't to be for Darren Davies' side as substitute Nzondo drilled the ball home past Evan Watts to give the Reds all three points.
Swansea City Under-18s are back in action next Saturday (1pm) against Coventry City Under-18s.
Barnsley Under-18s: Rogan Ravenhill, Josh McKay, Hayden Pickard, Jonathan Bland, Astin Brace, Alex Joof, Rafael Montiero, Jean Claude Makiessi, Josiah Dyer, Vimal Yoganation, Mylan Benjamin.
Subs: Trialist, Alex Anaman, Emmaisa Nzondo, Leo Farrell, Luis Lacey.
Swansea City Under-18s: Evan Watts, Sam Parker, Jada Mawongo, Richard Faakye, Seb Debroski, Dan Watts, Josh Carey, Kyrell Wilson, Geoff Bony, Iwan Morgan, Zany Myers.
Subs: Rohan Davies, Ewan Griffiths, Jacob Cook, Jack Cooper, Aimar Govea.