Rory Donnelly's injury time strike helped Swans Under-21s make it back-to-back league victories with a 2-1 win away at Crystal Palace.
Kris Scott, with his first goal for the U21s, opened the scoring for the visitors, only for Sullay Kaikai to equalise for the Eagles with only three minutes left on the clock.
However, with just seconds remaining, Donnelly side-footed home the winner after latching onto Scott's pass across the area.
The Swans were disappointed to enter the half-time interval at 0-0, having created several opportunities to break the deadlock while dominating possession.
After Kaikai rattled the bar from a 25-yard free-kick for the home side, some good build-up play between Scott and Kenji Gorre nearly led to Donnelly opening the scoring for the Swans.
The young striker found himself in a good position, but he drilled his shot just wide of the target.
The visitors also had a penalty shout turned down after Alex Bray looked as though he was brought down inside the box, but the referee deemed the challenge on Bray to be fair.
Nevertheless, the Swans returned from the half-time break, picking up from where they left off in the first 45 - looking dangerous on the attack.
A couple of chances came Crystal Palace's way as Kaikai went close with a header, before Alex Wynter's scuffed shot nearly trickled in off of Jernade Meade, but it was Swansea who took the lead.
Just past the hour mark, Kristian O'Leary's side were rewarded for their good performance when Henry Jones' cut-back found Scott, who easily converted from six yards.
But with three minutes of normal time remaining, the Eagles grabbed an equaliser through Kaikai, who steered his effort past Gregor Zabret.
It looked as though both sides would come away from the game with a point, only for Donnelly to latch onto Scott's pass and side-foot past the Palace goalkeeper with one of the last kicks of the game - his fourth goal in five matches.
CRYSTAL PALACE U21s: Alexander, Taylor, Williams, Dymond, Inniss, Chambers, Kaikai, Wynter, Sekajja, Guedioura (Tieku, 51), De Silva (Croll, 19).
SUBS: Fitzsimons, Udumaga
SWANSEA CITY U21s: Gregor Zabret, Liam Shephard, Daniel Alfei, Scott Tancock ©, Jernade Meade, Henry Jones, Lee Lucas, Kris Scott, Kenji Gorre (James Loveridge, 77), Alex Bray, Rory Donnelly.
SUBS: Oliver Davies, Alex Gogic, Keston Davies, Ryan Hedges.