THE Reds' eight-year stay in the Championship came to an end on Saturday after a 3-1 defeat against Middlesbrough.
Danny Wilson's side, who went into the match four points adrift of safety with just two games remaining, knew a win was vital if they were to take it into another nail-biting final day decider.
Three wins from their last five away games had provided Barnsley with optimism, and a gutsy first-half display would have added to that having repelled constant home pressure.
Boro again started brightly after the break, but it was the Reds who led through Jean-Yves M'voto's clever finish from a Martin Cranie cross to put them 1-0 up.
However, that short-lived advantage only lasted a minute and the hosts were back on terms through Lee Tomlin.
As the Reds desperately searched for a winner in the closing stages, the hosts hit them and took the lead in the 90th minute to break Barnsley's hearts. Albert Adomah's shot was blocked, but Danny Graham's rebound found the back of the net.
Tomlin grabbed his second and Middlesbrough's third three minutes into injury time to ensure victory after playing a neat one-two with Adomah.
"It is a sad day for everyone connected with the club," Danny Wilson said. "We will start planning for next season. The boys are hurting like mad.
"There will be a lot of changes, I'm sure, but it will be for the better.
"You can't fault the boys. It's a horrible feeling, but without the fans we probably would have folded before. They're true fans."
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