Striker Barry Conlon struck twice for Barnsley in the first half to help them on the way to ending Bournemouth's eight-match unbeaten run in the league with a 3-1 win at Dean Court.
Conlon took full advantage of defensive lapses from Shaun Maher and Eddie Howe to put his side into a commanding 2-0 lead at half-time and on their way to their first win in seven games.
The striker had no problem beating goalkeeper Neil Moss from the penalty spot on 19 minutes after he had been hauled down by Maher in the area, who was robbed of possession as he tried to dribble out of his own box.
Conlon then added a second nine minutes before the break after Howe's clearing header could only find Michael Chopra in space. Chopra played a pass over the unfortunate centre back's head for his strike partner to run onto and easily beat Moss.
It could have been worse for Bournemouth with Moss performing heroics to keep out Anthony Kay's magnificent volley from 30 yards just after the half-hour mark.
Bournemouth, who had come into the game as the division's leading scorers with 29 goals, began the second half in far brighter fashion and had reduced the deficit within six minutes of the restart through Wade Elliott.
Elliott raced on to a through ball from James Hayter before dispatching a deflected shot past goalkeeper Ross Turnbull and into the far left corner.
But Barnsley were always dangerous in attack and it was no surprise when Chopra restored their two-goal lead in the 69th minute.
The on-loan Newcastle striker had missed a far easier chance less than 60 seconds earlier when he shot wide of an unguarded goal, but had no trouble in chipping Moss from the edge of the area after beating Bournemouth's offside trap.