Paul Coutts' last-gasp equaliser for visitors Derby denied Barnsley a win which would have lifted them out of the Championship relegation zone.
The Scottish midfielder connected with substitute Michael Jacobs' corner to earn the Rams a much-needed point in their scrap to avoid the drop.
Coutts' finish cancelled out Chris O'Grady's 47th-minute strike for the hosts, who remain second bottom.
The draw with Derby saw Barnsley remain in the relegation zone on 50 points, a figure two points higher than the total they reached last season, when they finished fourth from bottom
And Derby now find themselves four points clear of the drop zone.
After the Rams had enjoyed the majority of the first-half possession and chances, Barnsley broke the deadlock two minutes after the interval with O'Grady volleying in a cross from impressive debutant Andrai Jones.
The former Leicester and Sheffield Wednesday striker succeeded where Barnsley striker Jason Scotland had failed in the first half, when he spurned two good chances in the opening 15 minutes.
But the visitors responded strongly before the break, Tykes keeper Luke Steele keeping the home side in the game as he denied efforts from Rams trio Jeff Hendrick, Ben Davies and Jake Buxton.
After the O'Grady opener, Barnsley nearly doubled their lead as Tomasz Cywka's 18-yard effort was well saved by Frank Fielding in the Derby goal.
But the Rams came back into it, Chris Martin firing over from 25 yards as the visitors searched for the equaliser.
And the mounting pressure told as Coutts' late header meant Derby avoided a third successive league defeat.
Barnsley manager David Flitcroft:
"The players are feeling the pressure of the situation, there's no doubt about it.
"It was a brave performance, but we didn't get the result we wanted.
"It's not a difficult one to take, it's just disappointment. It's an emotion we're going to have to soon get over."
Derby boss Nigel Clough:
"I thought we thoroughly deserved a point, but it really should have been three after the first-half performance.
"Considering the circumstances it was good to get something considering we were 1-0 down in stoppage time. You take your point.
"That point keeps our head above water with only three games to go. There's still quite a few teams below us in the table."
Full Time The referee signals the end of the game.
90:00 +2:23 Substitution
Substitution Chris Martin goes off and Valentin Gjokaj comes on.
90:00 +0:03 Substitution
Substitution Tomasz Cywka leaves the field to be replaced by Marlon Harewood.
Assist by Michael Jacobs.
90:00 +0:03 Goal scored
Goal! - Paul Coutts - Barnsley 1 - 1 Derby Paul Coutts finds the net with a headed goal from inside the six-yard box. Barnsley 1-1 Derby.
Corner taken right-footed by Michael Jacobs,
Craig Forsyth takes the direct free kick.
Booking The referee cautions Jacob Mellis for unsporting behaviour.
Michael Jacobs fouled by Jacob Mellis, the ref awards a free kick.
Unfair challenge on Jim O'Brien by Jeff Hendrick results in a free kick. Martin Cranie takes the free kick.
Free kick awarded for a foul by Chris O'Grady on Richard Keogh. Richard Keogh restarts play with the free kick.
Paul Coutts gives away a free kick for an unfair challenge on Chris O'Grady. The free kick is swung in right-footed by Scott Wiseman, clearance by Richard Keogh.
Paul Coutts produces a right-footed shot from long range that goes harmlessly over the bar.
Substitution Chris Dagnall joins the action as a substitute, replacing Jason Scotland.
Conor Sammon is flagged offside by the assistant referee. Free kick taken by Luke Steele.
Effort from just outside the area by Chris Martin goes over the target.
Substitution (Derby) makes a substitution, with Conor Sammon coming on for Mason Bennett.
Paul Coutts fouled by Jason Scotland, the ref awards a free kick. Craig Forsyth takes the direct free kick.
Unfair challenge on David Perkins by Jeff Hendrick results in a free kick. David Perkins takes the direct free kick.
Ben Davies takes the free kick.
Substitution (Derby) makes a substitution, with Michael Jacobs coming on for Kieron Freeman.
Unfair challenge on Craig Forsyth by Tomasz Cywka results in a free kick.
The ball is swung over by Reuben Noble-Lazarus, save by Frank Fielding.
Ben Davies takes a outswinging corner from the right by-line played to the near post, clearance made by Martin Cranie.
Jason Scotland handles the ball and concedes a free kick. Direct free kick taken by Paul Coutts.
Chris O'Grady fouled by John Brayford, the ref awards a free kick. Free kick crossed by Jim O'Brien, Paul Coutts makes a clearance.
Unfair challenge on Ben Davies by Andrai Jones results in a free kick.
The referee blows for offside against Chris Martin. Luke Steele takes the direct free kick.
Booking Andrai Jones goes into the book for unsporting behaviour.
Ben Davies fouled by Tomasz Cywka, the ref awards a free kick. Ben Davies crosses the ball in from the free kick.
Jacob Mellis challenges Paul Coutts unfairly and gives away a free kick. Craig Forsyth restarts play with the free kick.
Mason Bennett concedes a free kick for a foul on David Perkins. Luke Steele restarts play with the free kick.
Reuben Noble-Lazarus challenges John Brayford unfairly and gives away a free kick. Free kick crossed by Ben Davies, Tomasz Cywka makes a clearance.
Shot by Tomasz Cywka from 18 yards. Save by Frank Fielding.
46:59 Goal scored
Goal! - Chris O'Grady - Barnsley 1 - 0 Derby Chris O'Grady finds the net with a goal from inside the box to the bottom left corner of the goal. Barnsley 1-0 Derby.
Inswinging corner taken from the right by-line by Reuben Noble-Lazarus, Paul Coutts manages to make a clearance.
Free kick awarded for an unfair challenge on Tomasz Cywka by Ben Davies. Scott Wiseman restarts play with the free kick.
The game restarts for the second half.
45:00 +1:38 Half time
Half Time The match has reached half-time.
Kieron Freeman fouled by Jim O'Brien, the ref awards a free kick. Ben Davies crosses the ball in from the free kick, clearance by Martin Cranie.
Outswinging corner taken left-footed by Reuben Noble-Lazarus from the left by-line, John Brayford manages to make a clearance.
Foul by Jake Buxton on Jason Scotland, free kick awarded. Direct free kick taken by Jacob Mellis.
Shot by Chris O'Grady. Save by Frank Fielding.
Paul Coutts challenges Tomasz Cywka unfairly and gives away a free kick. Free kick taken by David Perkins.
Unfair challenge on Ben Davies by Jacob Mellis results in a free kick. Direct free kick taken by Craig Forsyth.
Jim O'Brien is caught offside. Frank Fielding takes the direct free kick.
Substitution Andrai Jones joins the action as a substitute, replacing Bobby Hassell.
Mason Bennett takes a shot. Luke Steele makes a save. Chris Martin takes a shot. Blocked by Martin Cranie. Chris O'Grady sends in a cross, save made by Frank Fielding.
Outswinging corner taken right-footed by Paul Coutts from the right by-line, Headed effort on goal by Jake Buxton from inside the penalty box misses to the right of the target.
Free kick awarded for an unfair challenge on Richard Keogh by Chris O'Grady. Frank Fielding restarts play with the free kick.
Free kick awarded for a foul by Kieron Freeman on David Perkins. Free kick taken by Martin Cranie.
Jeff Hendrick takes a shot. Save made by Luke Steele.
Chris Martin fouled by Martin Cranie, the ref awards a free kick. The free kick is delivered right-footed by Ben Davies from right channel, clearance by Martin Cranie. Jeff Hendrick takes a shot. Save made by Luke Steele.
Unfair challenge on Jake Buxton by Chris O'Grady results in a free kick. Free kick taken by Frank Fielding.
The ball is sent over by Craig Forsyth.
Ben Davies takes a long range shot harmlessly clearing the crossbar.
Jeff Hendrick takes a shot. Fantastic save by Luke Steele.
Free kick awarded for a foul by Kieron Freeman on Martin Cranie. Reuben Noble-Lazarus restarts play with the free kick.
Jason Scotland takes a shot. Save by Frank Fielding.
Free kick awarded for an unfair challenge on Scott Wiseman by Ben Davies. Bobby Hassell takes the free kick.
Kieron Freeman fouled by Jim O'Brien, the ref awards a free kick. John Brayford takes the direct free kick.
Free kick awarded for an unfair challenge on Ben Davies by Chris O'Grady. Paul Coutts takes the free kick.
The ball is sent over by Scott Wiseman, John Brayford manages to make a clearance.
Jason Scotland takes a shot from deep inside the box clearing the bar.
The offside flag is raised against Kieron Freeman. Direct free kick taken by Luke Steele.
Free kick awarded for an unfair challenge on Jason Scotland by Jeff Hendrick. David Perkins takes the free kick.
Unfair challenge on Mason Bennett by Martin Cranie results in a free kick. The free kick is delivered right-footed by Ben Davies from right wing, David Perkins manages to make a clearance.
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