LEE JOHNSON had his return to Oakwell ruined as substitute Adam Hammill struck in stoppage time to rescue a point for the Reds.
Barnsley’s Marley Watkins headed home his fourth goal of the season but captain Sam Winnall missed a penalty in first-half stoppage time.
It was an important miss as Lee Tomlin showed how it should be done when he drove home Bristol’s equaliser from the spot after the break and later set up Chelsea loanee Tammy Abraham to make it 2-1.
The Reds were not finished and Hammill struck as the game entered the four minutes of stoppage time.
Reds boss Paul Heckingbottom said: “It would have been a travesty if we hadn’t got anything out of it, but when you’ve been behind and you score a late goal, you’re satisfied with a point.
“There were lots of pleasing things and we’ll look back and think we should have won the game.
“The game could have been easy for us and then you’re 2-1 down and you’re scrambling to get a point and we managed to do it.
“The character of the lads is fantastic and, from the first minute to the last, they were great. Even in the build-up, helping Josh Kay through his debut.
“We had a lot of players missing but to a man they were fantastic. It just shows the value of all the squad.
“He (Hammill) has got great talent and if you want anyone in that position with the ball, it’s Adam Hammill. Luckily for us, he scored.”
Johnson made his first trip to Barnsley since leading the Reds to the JP Trophy final and immediately shipping out to join home-town club Bristol in February, steering them clear of Championship relegation trouble as the Reds added promotion to their JP Trophy success under Heckingbottom.
Barnsley went into the game shorn of their key central midfield duo in captain Conor Hourihane and Josh Scowen, who were both suspended. It gave 19-year-old development player Josh Kay the chance to make his debut after signing from AFC Fylde in February.
Kay lined up alongside Sam Morsy, while Angus MacDonald and Adam Jackson continued as the central defensive pairing with Marc Roberts ruled out by a bug.
Up against the Reds back four wasAbraham, who has made such an impression since signing on loan from Chelsea, notching eight league goals prior to kick-off.
Also in the visitors’ line-up was left-back Scott Golbourne, who made 47 appearances for the Reds in 2012-13.
A great sliding challenge by Jackson prevented Abraham capitalising on a ball down the right channel from Aaron Wilbraham after which things became somewhat fractious.
However, it was the Reds who took a 21st minute lead when Andy Yiadom came inside and curled over a delightful cross which Watkins, rising with Winnall, connected with a downward header which beat the dive of Frank Fielding.
Morsy was the first into the book for a trip on the niggling Tomlin, Wilbraham followed for dissent and Winnall suffered a gashed left eyebrow after being caught by an elbow in an off-the-ball challenge which went unpunished.
The Reds captain returned with his head bandaged after which Kay went into the book for one foul too many, this time on Tomlin, who curled wide the ensuing free-kick.
Armstrong tested Fielding from outside the area in the 45th minute and Kay fizzed a shot over in the five minutes of stoppage time, during which Korey Smith was also carded for dissent.
Then Barnsley should have made it 2-0 when Golbourne tripped Winnall a yard inside the area but the Reds captain drove his spot-kick down the middle and Fielding, going to his left, blocked the ball with his legs.
Neither side made a change at the break and MacDonald had a chance to make it 2-0 after Fielding missed a free-kick from Ryan Kent, leaving the unmarked central defender to volley over from beyond the far post.
It was 1-1 in the 58th minute when Golbourne crossed and the outstreched hand of Jackson diverted the ball away from the strikers, conceding a penalty which Tomlin drove powerfully down the middle as Adam Davies went to his right.
Armstrong almost got Barnsley back in front when he smashed a shot from the left corner of the area against the bar.
Yiadom and Kent also had fierce drives blocked before Bristol made a double substitution in a bid to stem the pressure.
Joe Bryan almost made an immediate impact, driving down the middle and seeing his shot deflected narrowly wide before he also went in the book for a lunge on James Bree.
Bryan then crossed and Wilbraham’s downward header looked to be going in but Davies dived to his left and diverted it against the post and away to safety.
Bree’s dangerous cross was almost headed into his own net by Aden Flint before Adam Hammill replaced Watkins.
The visitors struck to make it 2-1 in the 77th minute, Wilbraham chesting down for Tomlin to go wide of Jackson before a reverse pass inside the area set up Abraham for a simple finish.
Armstrong’s speed took him into the area from the left but he could only poke the ball over the bar as Fielding rushed out.
Kay received deserved applause when he was replaced by Ryan Williams in the 88th minute and there was a dramatic finale as Hammill cut in from the left and bent a low shot beyond Fielding into the far corner.
There was still time for Bryan to break again but Davies parried the fierce shot.
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