Paul Heckingbottom was left deflated after seeing his Barnsley side suffer defeat to Ipswich Town on their first Championship outing at Oakwell.
The Tykes were ahead at the interval following a goal from Tom Bradshaw, but the introduction of David McGoldrick and Martyn Waghorn for the start of the second half inspired an impressive revival from the visitors.
McGoldrick levelled the scores and Waghorn struck the winner to make it three wins in a row for the Suffolk club.
Heckingbottom said: “It’s a tough one to take that after starting how we did, taking the lead and creating numerous chances.
“To lose a game when they only had two shots on target is deflating, but the performance was there and there were lots of good things.
“I think we should have been out of sight at half-time. Mick McCarthy made changes at half-time and brought on a lot of experience. They went a lot more direct and won a lot of second balls.
“We had to weather a 10-minute storm when they got their first goal and after that I thought we were back on top.
“We played well today and lost, so we will have to play well on Tuesday night and ensure that we win.”
Barnsley took the lead after 15 minutes when Ryan Hedges’ cross from inside the area to the far post was met by the unmarked Bradshaw.
The visitors equalised when a Jonas Knudsen cross picked out McGoldrick, before Waghorn, who produced an impressive finish.
Barnsley: Davies, McCarthy, Jackson, MacDonald, Pearson, Joe Williams, Hammill (Barnes 80), Potts, Moncur, Hedges (Payne 78), Bradshaw (Ugbo 57). Unused substitutes: Townsend,Pinnock,Mowatt,Bird.
Ipswich: Bialkowski, Spence, Chambers, Knudsen, Iorfa, Downes (McDonnell 77), Skuse, Nydam (Waghorn 46), Kenlock (McGoldrick 46), Sears, Garner. Unused substitutes: Woolfenden, Gerken, Celina, Rowe.
Referee: G Eltringham (Tyne & Wear).