BARNSLEY are down in the bottom four after defeat to one of manager Danny Wilson’s former clubs
Swindon scored three second-half goals to stretch their unbeaten run in League One to seven games and condemn the Reds to a fifth successive game without victory.
Wing-back Nathan Byrne opened the scoring after the break with a low shot into the bottom corner.
He then set up Jake Reeves for a close-range finish, before Andy Williams swept in his fourth goal in four games.
Centre-back Jean-Yves M’Voto volleyed over for the Tykes, Devante Cole had a shot saved by Wes Foderingham and Dale Jennings made an impact from off the bench out wide.
But Reds assistant manager Chris Hutchings said: “It was very disappointing. I think first half we did okay, we tried to nullify them getting the ball at the back, which is their game and they’re very good at it.
“But as soon as we conceded, we folded a little bit and we were looking for characters and they didn’t come forward.
“We had a couple of chances, but we didn’t take them in the end. We need to go back to basics, be hard to beat and then take it from there.”
Swindon chief Mark Cooper said: “We knew at some point in the game their energy may go a little. We kept the back door shut and waited for that moment. Once we scored, it was a really good performance.”
Barnsley: Turnbull, Bree, Mvoto, Nyatanga, Dudgeon, Bailey, Cranie (Treacy 72), Hourihane, Hemmings, Winnall (Jennings 64), Cole. Unused substitutes: Brown, Berry, Davies, Noble-Lazarus, Lita.
Swindon Town: Foderingham, Nathan Thompson, Stephens, Turnbull, Byrne, Luongo, Louis Thompson (Reeves 77), Kasim, Bell, Michael Smith, Obika (Williams 20). Unused substitutes: Waldon, Barker, Barthram, Belford, Rodgers.
Referee: C Kavanagh (Lancashire).
Man of the match: Nathan Byrne.