Tommy Rowe denied Barnsley a battling point at London Road with a late winner to earn Peterborough United an important victory this afternoon.
The home side led at the break thanks to a free kick from Michael Bostwick, who guided home a measured finish from the edge of the area.
Dwight Gayle and Lee Tomlin looked dangerous for Posh from the outset as they went in search of a fourth win in five matches.
Bostwick broke the deadlock on 30 minutes with a neat set piece on the edge of the area.
Joe Newell came close to doubling the visitors' advantage with a low strike before Barnsley had their best chance of the half in stoppage time.
A free kick from Tom Kennedy took a nasty deflection and needed a strong hand from Robert Olejnik to keep the Tykes goalless at the break.
Managerless Barnsley levelled 12 minutes from time when Marlon Harewood guided a cross into the bottom corner with a shot from just outside the penalty area.
The Tykes were unable to hold on as Posh pressed for a winner in the closing stages, with Rowe doing the damage four minutes from the end.
