Match ends, Barnsley 2, Birmingham City 0.
Birmingham City's dismal Championship away form continued as Tom Bradshaw's early goal set Barnsley on the way to victory at Oakwell.
Bradshaw was left with an easy finish from Harvey Barnes' ball from the left.
And it took a superb low save by Tomasz Kuszczak to prevent Lloyd Isgrove doubling the lead before half-time.
Birmingham struggled to create chances and the home side sealed the points when Zeki Fryers scored from a free-kick after Bradshaw was fouled.
The on-loan left-back's first senior goal lifted Barnsley three places to 16th in the table, with Birmingham - who have still only taken one point away from home - dropping into the relegation places.
Steve Cotterill made five changes after Blues' home defeat by Brentford in midweek but, after Marc Roberts tested Barnsley keeper Adam Davies with an early header, the home side went straight up the other end and Bradshaw gave them the lead.
Birmingham have only scored eight Championship goals this season - the lowest total in the entire EFL - but they were unable to add to that meagre tally as Davies foiled Lukas Jutkiewicz and Jota.
Barnsley's margin of victory could even have been greater, with George Moncur curling just wide after Fryers had made it 2-0 when his dead-ball delivery found its way into the net.
Barnsley boss Paul Heckingbottom:
"We've probably dominated games as much, if not more, than that at Oakwell and either drawn or lost, so it's nice to put in a good performance and get a good win.
"We were in a strong position early doors, which was good. I think the most pleasing bit for me was how we dealt with them.
"I've just been speaking about hitting the target. They think I'm silly when I shout it that much, but cheap goals, you get them.
"For Fryers' free-kick, he's aiming for goal or somebody to get a touch."
Birmingham manager Steve Cotterill told BBC WM:
"There's one or two things that we'll cling onto. We didn't get outworked. And we're inches away from going 1-0 up. That's happened a couple of times.
"That would probably give us the fillip and the boost that we need out there. To then go and concede is a real kick in the teeth.
"And the first goal came on the counter. They got a cross into the box and scored off, which is disappointing.
"From then on, we worked a couple of opportunities, but we did not quite get a shot off. At the moment we're looking for the perfect shot, which you don't get."
- 11IsgroveSubstituted forHammillat 61'minutes
- 15BarnesSubstituted forHedgesat 79'minutes
- 9BradshawSubstituted forThiamat 88'minutes
- 4RobertsBooked at 61mins
- 6KieftenbeldBooked at 38mins
- 23CotterillSubstituted forAdamsat 69'minutes
- 10JutkiewiczSubstituted forBogaat 75'minutes
- James Linington
- Shots on Target
Second Half ends, Barnsley 2, Birmingham City 0.
Attempt missed. George Moncur (Barnsley) right footed shot from outside the box is high and wide to the right. Assisted by Ryan Hedges.
Attempt missed. Jeremie Boga (Birmingham City) right footed shot from outside the box is high and wide to the right. Assisted by Sam Gallagher.
Substitution, Barnsley. Mamadou Thiam replaces Tom Bradshaw.
Attempt saved. Andy Yiadom (Barnsley) right footed shot from outside the box is saved in the centre of the goal. Assisted by Tom Bradshaw.
Attempt saved. Tom Bradshaw (Barnsley) right footed shot from the centre of the box is saved in the centre of the goal. Assisted by Brad Potts.
Attempt blocked. Harlee Dean (Birmingham City) right footed shot from outside the box is blocked. Assisted by David Davis.
Attempt missed. Jota (Birmingham City) left footed shot from the centre of the box misses to the right. Assisted by Che Adams.
Attempt missed. George Moncur (Barnsley) right footed shot from the left side of the box is close, but misses to the right. Assisted by Ryan Hedges.
Attempt saved. Jota (Birmingham City) left footed shot from outside the box is saved in the bottom right corner.
Substitution, Barnsley. Ryan Hedges replaces Harvey Barnes.
Attempt missed. George Moncur (Barnsley) right footed shot from outside the box is too high. Assisted by Harvey Barnes.
Substitution, Birmingham City. Jeremie Boga replaces Lukas Jutkiewicz.
Offside, Birmingham City. Marc Roberts tries a through ball, but Che Adams is caught offside.
Corner, Barnsley. Conceded by Jonathan Grounds.
Andy Yiadom (Barnsley) wins a free kick on the right wing.
Foul by Sam Gallagher (Birmingham City).
Joe Williams (Barnsley) wins a free kick in the defensive half.
Foul by Che Adams (Birmingham City).