Debutant Joe Allen gave Wales Under-21 victory in a seven-goal friendly thriller against Sweden on Tuesday.
Joe Allen scored a fine winner on his Wales Under-21 debut
Ola Toivonen hit a first-half hat-trick for the hosts - two from the penalty spot - before David Edwards added to David Cotterill's earlier effort.
Sam Vokes brought Wales level on 58 minutes, scoring his second goal in as many matches for Brian Flynn's side.
The superb comeback was complete three minutes later when 17-year-old Swansea midfielder Allen volleyed home.
Malmo's Toivonen opened the scoring from the spot on 19 minutes after he had been fouled in the penalty area by Middlesbrough defender Rhys Williams.
Wigan striker Cotterill did his hopes of a recall to the senior squad no harm when he equalised with a cool finish on 27 minutes after a fine Shaun MacDonald run.
Toivonen clinically netted another spot-kick on the half-hour after Wrexham's Mike Williams' mistimed lunge floored Johan Oremo.
Swansea winger MacDonald then wasted a great opportunity from 12 yards, and Wales were left to rue the miss when Toivonen lifted the ball into an empty net on 44 minutes to put Sweden 3-1 up.
But the young Dragons found an immediate reply during first-half stoppage-time as captain Edwards side-footed past Johan Dahlin after confusion in the home defence.
Cardiff City's highly-rated 16-year-old Aaron Ramsey replaced Matt Collins in central midfield after the break, and it was another substitute who brought Wales level.
Bournemouth's Vokes had only been on the field for 20 seconds - replacing the impressive Cotterill - when he scored after his header had rebounded off the post.
And three minutes later the Welsh had their winner when MacDonald made inroads up the right and delivered for Allen to deftly flick the ball into the net.
Wales' next match is a Uefa Championship qualifier away to France on 7 September.
Wales Under-21 manager Brian Flynn:
"We had some really big performances from the players and it was a thoroughly deserved victory.
"We had two debatable penalties given against us, but the players showed a lot of composure, character and grit to win the game.
"Five of our boys were missing after being called up to the senior squad, and we ended the game with a 16-year-old, two 17-year-olds and three 18-year-olds playing.
"If they keep the standard they showed tonight, then the future is looking bright."
Sweden U21: Dahlin, Westerberg, Bjarsmyr, Svensson, Hellstrom, Ahman-Persson, Castro-Tello, Avdic, Vasquez, Oremo, Toivonen.
Subs: Hansson, Lustig, Ronningberg, Wernbloom, Elm, Lawan, Pode.
Wales U21: O Williams (R Taylor 46), Blake, Jacobson, Collins (Aaron Ramsey 46), R Williams (N Taylor 57), M Williams, Allen (Warlow 83), Edwards, Evans (Church 76), Cotterill (Vokes 57), MacDonald.
Sub Not Used: Bradley.
Referee: Svein-Erik Edvartsen (Norway).