BOOS rang around the ground at full time as Rotherham United picked up their first win at Oakwell since 1970 thanks to Kian Spence's second half goal.
Barnsley had won their last seven meetings against Rotherham before this game, including earlier this season in the EFL Cup when they came from behind at Oakwell to win 2-1 thanks to goals by Jon Russell and Adam Phillips.
Hourihane made four changes to the team that drew 2-2 with promotion-chasing Bradford City last weekend.
David McGoldrick, Marc Roberts, Patrick Kelly and Mael de Gevginey came in.
Adam Phillips and Earl were not in the squad while Tennai Watson and Caylan Vickers dropped to the bench.
Rotherham, managed by Matt Hamshaw, started former Reds player Josh Benson and Ar'Jany Martha who netted at Oakwell in the league cup earlier this season.
Barnsley should have opened the scoring after two minutes.
Luca Connell's corner was flicked on in the Rotherham area and found McGoldrick at the back post, but his header hit the post and went out of play.
The Reds were on top for the opening half an hour and Reyes Cleary, off the back off his screamer last weekend in West Yorkshire, tormented Joe Rafferty on the left.
Luca Connell had a free-kick superbly saved by Dawson in the Rotherham goal on 35 minutes.
Joe Powell came closest for the Millers on the stroke of half-time but his free-kick from a tight angle went just over.
McGoldrick had the first chance of the second half after playing a neat one-two with Keillor-Dunn before shooting just wide with the outside of his boot.
The Millers took the lead on 64 minutes as Kian Spence's powerful strike flashed past Cooper in the Barnsley goal, sending the away end wild.
The hosts seemed to struggle after the goal and the away side had chanced to go even further in front.
Rotherham brought on two defenders in the final minutes and did well to close out the game.
It was Rotherham's first win at Oakwell since 1970 and the result extended Barnsley's winless run in the league to five games.
The Millers are now just one point behind Barnsley in the League One table.
