
The Baggies were looking to finish their dismal season on a high - and they went into the break with a two goal lead.
First Karlan Grant stroked home from the spot after Jayson Molumby went down in the box, before Adam Reach latched onto a long ball from David Button to lob the Barnsley keeper.
It got better for a dominant Albion after the break as Matt Clarke stroked home before Grant's deft chip made it four.
But the forward passed up the chance to make it a hat-trick and 19 goals for the campaign - when his late spot kick was saved by Barnsley stopper Jack Walton.