Barnsley suffered their first defeat under Valerien Ismael as they went down 3-0 at Cardiff City on Tuesday.
The hosts took the lead in the fourth minute then doubled it just before half-time from the penalty spot.
The Bluebirds added another after the break against a Reds side who delivered one of their worst performances of the season and saw their five-game unbeaten run end.
Barnsley were very poor in the first half, failing to make most of their passes while playing aimless long balls to a small front three and badly struggling to make from Cardiff's dangerous crosses and set pieces. The second half was more even but the visitors never really looked like getting back into the match.
Ismael, who had won his first two games, brought in Elliot Simoes for the injured Callum Brittain, with Dominik Frieser moving to right wing-back.
Barnsley were exposed after just three minutes when a simple long ball played in Junior Hoilett on the left of the box and goalkeeper Jack Walton rushed out to just beat him to the ball with a good block.
But it was 1-0 seconds later when no defenders closed down Joe Bennett on the left wing after he got the ball from a throw and he sent in a cross which Michal Helik missed, leaving Hoilett to bring it down and beat Walton from close range.
It could have been 2-0 after five minutes but Robert Glatzel glanced wide a right-wing cross by Harry Wilson with a headed chance. Centre-back Curtis Nelson then headed a right-wing Marlon Pack corner straight at Walton from five yards out in the 19th minute.
Glatzel came close again when he stuck out his right foot to divert another Bennett cross towards goal ten yards out but Walton dived down to his left to save easily.
Ismael then brought off the ineffective Simoes for Clarke Oduor who went to left wing-back with Styles moving to the right and Frieser going onto the right of the front three.
Former Barnsley striker Kieffer Moore should have doubled the lead but his five-yard header was too close to Walton, who made a fine save, after Morrison slid in to volley a left-wing free-kick back across goal. Walton also denied Glatzel comfortably after the German striker shot from the left of the box at a tight angle.
The Reds had their best chance of the first half when Matty James' excellent pass over the top was well brought down by Chaplin but goalkeeper Alex Smithies made a good block then Schmidt's shot was blocked by Morrison.
Wilson won a penalty just before the break when he swapped clever passes in the box with Moore then Helik lunged in and tripped him on the right of the six yard box. Joe Ralls netted the penalty.
Glatzel missed his fourth chance of the game on the hour-mark when his header ten yards out from a right-wing Ralls cross was easily caught by Walton.
Schmidt then headed a Chaplin corner onto a defender so the ball looped up and goalkeeper Smithies tipped over the bar. That was Schmidt's last action was he was instantly replaced by Victor Adeboyejo.
Wilson made it 3-0 on 77 minutes with a fine 20-yard effort which flew past Walton into the top right corner. Moore almost added a fourth after going one-on-one with Walton but the goalkeeper saved with his legs in injury-time.
Barnsley (3-4-3): Walton; Sollbauer, Helik, Andersen; Frieser, James (Halme 79mins), Mowatt, Styles; Simoes (Oduor 39mins), Schmidt Adeboyejo (65), Chaplin. Unused: Collins, Kane, Miller, Thomas. Yellow cards: James
Cardiff City (4-4-2): Smithies; Bacuna, Morrison, Nelson, Bennett; Wilson, Pack, Ralls (Vaulks 86mins), Hoilett; Moore, Glatzel (Ojo 67). Unused: Phillips, Bamba, Bagan, Whyte, Murphy. Goals: Hoilett 4, Ralls 44 (pen), Wilson 77.