Reds boss David Flitcroft has feared for weeks that his side’s survival could come down to Saturday’s final-day derby against Huddersfield.
Barnsley travel to Huddersfield’s John Smith’s Stadium rooted in the bottom three on goal difference, on 54 points.
Town are just three points above - in 18th - but could still fall through the relegation trapdoor - as could Sheffield Wednesday, who host Middlesbrough.
“We know what’s needed,” Flitcroft said.
“I’ve been saying for a while that it would come down to the Huddersfield match. Now let’s go there and finish the job off.
“I always felt we would give it a fighting shot and take it to the last day.”
Flitcroft has won almost half his games since taking charge of Barnsley in December, and he added: “I didn’t expect the points total needed to stay up.
“It’s crazy. So many teams have kept fighting so hard.
“What a league this is.”