Barnsley 1 (Davies 74)
Bristol City 2 (Adomah 14, Maynard 90+ 2)
A stoppage-time strike from hotshot Nicky Maynard stole the points when it seemed a draw was on the cards at Oakwell.
Substitute Craig Davies appeared to have rescued a point with his first Barnsley goal after Butterfield had rattled the angle in the second period when the Reds turned up the heat.
Keith Hill admitted he didn't know what to expect from Bristol City after Derek McInnes' appointment at Ashton Gate but found his side a goal down at the break in a rather uneventful first half at Oakwell.
The Reds started the brighter of the two sides with O'Brien looking lively down the right flank but Bristol did threaten through a Fontaine header at the other end.
In the 14th minute, as the game had barely found its rhythm, the visitors took the lead through Adomah. As Barnsley back-line waited for the offside flag, Maynard pounced onto a looping ball and laid back for winger Adomah to tap into the empty net.
Maynard should have made it two on 18 minutes, after rounding 'keeper Steele he lost his balance and scuffed wide when he seemed destined to double his side's lead.
The game hit a real sticky patch as neither team took hold of proceedings with chances few and far between until the 38th minute when Butterfield let fly from 20 yards - his left-footed effort was smartly saved by James and Gray was close to capitalising on the rebound but City cleared.
The Reds had Scott Wiseman to thank as Nicky Maynard's scuffed attempt appeared to be looping in but the defender cleared from off the line and out for a corner.
Right at the other end on 52 minutes, Andy Gray had the goal at his mercy but somehow scooped his three yard effort over after excellent work down the left from Drinkwater and McEveley.
Jacob Butterfield worked up some absolute magic with a wonderful shimmy before unleashing a sublime effort from 25 yards that hammered the angle of David James' goal on the hour mark.
The Oakwell crowd were patient with their side - as City were doing well in pressuring Barnsley - and were rewarded with an equalising goal with Craig Davies bagging his first Reds goal. McEveley made a wonderful run into the area and pulled back for the former Spireite to slot home.
The crowd had really come to life and the Ponty End roared on Perkins as the 'pocket rocket' steamed into the area and set up Davies who was this time denied by James with a great save.
Steele was brought into the second period as he denied Elliott's thunderbolt, and when it looked like Maynard was to snatch the winner from the rebound, McNulty appeared from nowhere to nick the ball from under his nose.
As soon as four minutes of stoppage time was indicated, Craig Davies took a long ball from Perkins down on his chest but his shot from the edge of the box was fairly tame and dealt with by James.
Just as the result seemed to be heading for a draw, Albert Adomah chased what seemed like a lost cause down the right and delivered for Maynard, who had time to turn a lash an effort into the top corner.
It was cruel on the Reds who deserved a point, but such is football.
The Reds: Steele, McEveley, Doyle (Perkins 69), Foster, O'Brien, Done (Davies 58) , Wiseman, McNulty, Butterfield, Drinkwater, Gray (Vaz Te 65).
Subs: Preece, Edwards.
Bristol City: James, Fontaine, Nyatanga, Elliott, Kilkenny, Woolford (Bolasie 66), Skuse, Cisse (Wilson 82), Adomah, McGivern.
Subs: Gerken, Stead.
Referee: Paul Tierney
Assistant Referees: Paul Kettlewell & Bob Roberts
Fourth Official: Alan Clayton
Attendance: 8,900 (354 away supporters).