Deji Oshilaja played the role of hero for Mansfield, scoring a goal in the 90th minute that secured their first victory in 15 matches and completing a double over Barnsley.
A thrilling 2-1 win helped Mansfield avoid matching their longest winless streak of 14 league games.
Mansfield's goalkeeper, Christy Pym, made a crucial double save in the 5th minute, stopping Stephen Humphreys in a one-on-one situation and then keeping out Josh Benson's follow-up.
In the 9th minute, Oshilaja missed a good chance to score, but Mansfield managed to take the lead shortly after with a goal from loanee Caylan Vickers.
Barnsley's goalkeeper, Jackson Smith, picked up an injury during the game and had to be substituted by Keiren Flavell.
In the second half, Barnsley managed to equalize with a goal from Benson, but Mansfield clinched the victory with Oshilaja's late goal.
In a dramatic ending, Oshilaja scored the winning goal for Mansfield from a cross by McLaughlin.