Birmingham helped their Championship survival hopes with a win at relegation rivals Peterborough.
Blues keeper Jack Butland saved from Tommy Rowe and Lee Tomlin before Nikola Zigic put the visitors ahead.
The Serbian poked home after Chris Burke's shot was parried by keeper Bobby Olejnik.
- Peterborough are now winless in the fixture in eight attempts stretching back to 1993.
Posh thought they should have had a penalty before Chris Burke's deflected 20-yard strike sealed Birmingham's win.
The win moved the visitors seven points clear of relegation, while bottom-of-the-table Peterborough were left four points from safety.
The home side had lost midfielder George Boyd, who joined Hull on loan after helping Posh to a 5-1 win over Millwall in midweek, but they began brightly.
They would have taken the lead but Butland saved impressively from Rowe before tipping Tomlin's follow-up effort over.
Instead, Zigic put Birmingham in front and Callum Reilly almost added to the lead when his 25-yard strike hit the crossbar.
Peterborough had a penalty appeal waved away, including when Nathaniel Mendez-Laing was sent crashing by City full-back Mitch Hancox.
Reilly also escaped a second yellow card after a challenge on Kane Ferdinand before a huge deflection from Burke's shot after 80 minutes beat Olejnik to put the visitors out of reach.
Peterborough manager Darren Ferguson: "If you're asking me whether or not the officials are good enough, the answer is nowhere near at this level.
"There were two big decisions in the game and the referee got both of them wrong as far as I am concerned.
"I see absolutely no reason why a forward would choose to go down when clean through and Nathaniel is adamant the Birmingham lad caught him.
"The assistant referee was 10 yards behind play so in no position to give a penalty while the referee clearly chose not to give one.
"I asked the referee why he didn't give the Birmingham lad a second yellow card and he said his foul was an accident, but again that's not how I saw it."
Birmingham boss Lee Clark : "You have to be delighted to win 2-0 on the road and that's certainly how I feel right now.
"A second successive clean sheet was particularly pleasing as solid defending is always the basis for success in football.
"We came here with a game plan and executed it very well. We had some outstanding performers, not least Chris Burke who has been back to his fine form of last season in recent games."
Live Text Commentary
Full Time The referee ends the match.90:00 +3:03
The offside flag is raised against Dwight Gayle. Jack Butland takes the free kick.90:00 +2:54
The ball is delivered by Lee Tomlin, Curtis Davies manages to make a clearance.90:00 +2:32
Outswinging corner taken by Grant McCann from the left by-line, clearance made by Curtis Davies.90:00 +1:43
Corner from the right by-line taken by Grant McCann, clearance made by Steven Caldwell.90:00 +1:09 Substitution
Substitution Nikola Zigic goes off and Hayden Mullins comes on.89:13
Grant McCann takes a shot. Blocked by Curtis Davies. Corner taken by Grant McCann.87:17
Michael Bostwick challenges Wes Thomas unfairly and gives away a free kick. The ball is crossed by Wade Elliott, Wes Thomas takes a shot. Save by Robert Olejnik.86:22
Gabriel Zakuani gives away a free kick for an unfair challenge on Wes Thomas. Steven Caldwell restarts play with the free kick.85:25
The ball is sent over by Paul Caddis, blocked by Tommy Rowe. Corner from the right by-line taken by Christopher Burke, Header by Curtis Davies from deep inside the penalty area misses to the left of the target.84:29
The ball is sent over by Danny Swanson, Steven Caldwell makes a clearance. Inswinging corner taken by Grant McCann.83:38
Foul by Jonathan Spector on Grant McCann, free kick awarded. Direct free kick taken by Grant McCann.82:47
The referee blows for offside against Nikola Zigic. Robert Olejnik restarts play with the free kick.81:50
The ball is delivered by Nathaniel Mendez-Laing, Steven Caldwell makes a clearance.79:21 Goal scored
Goal! - Christopher Burke - Peterboro 0 - 2 Birmingham Christopher Burke scores a goal from just outside the penalty box to the bottom left corner of the goal. Peterborough 0-2 Birmingham.78:18 Substitution
Substitution Wes Thomas on for Peter Lovenkrands.75:27 Substitution
Substitution Callum Reilly leaves the field to be replaced by Morgaro Gomis.75:27
Long range effort by Callum Reilly goes harmlessly over the bar.73:49
Callum Reilly gives away a free kick for an unfair challenge on Kane Ferdinand. Free kick crossed right-footed by Danny Swanson, Jack Butland makes a save.72:15
Effort on goal by Christopher Burke from deep inside the penalty area misses to the right of the target.
Nathaniel Mendez-Laing is adjudged to have handled the ball. Free kick taken by Jack Butland.69:15 Booking
Booking Michael Bostwick goes into the book.69:13
Free kick awarded for an unfair challenge on Nikola Zigic by Michael Bostwick. Free kick taken by Steven Caldwell.67:57
The ball is sent over by Mark Little, Lee Tomlin takes a shot. Save made by Jack Butland.67:46
Dwight Gayle produces a cross, Curtis Davies manages to make a clearance.66:52
Free kick awarded for an unfair challenge on Mitch Hancox by Mark Little. Free kick crossed right-footed by Wade Elliott, save by Robert Olejnik.66:38
The ball is sent over by Christopher Burke, save by Robert Olejnik.65:12
Shot from just outside the box by Callum Reilly misses to the left of the goal.64:24
Mark Little takes a shot. Steven Caldwell gets a block in.64:17
A cross is delivered by Nathaniel Mendez-Laing, Curtis Davies makes a clearance.63:27
The ball is delivered by Tommy Rowe.62:09
Jonathan Spector gives away a free kick for an unfair challenge on Michael Bostwick. Michael Bostwick restarts play with the free kick.61:06
Tommy Rowe fouled by Jonathan Spector, the ref awards a free kick. Free kick taken by Lee Tomlin. Michael Bostwick has an effort at goal from outside the penalty box which goes wide right of the target.60:12 Substitution
Substitution Danny Swanson on for Joe Newell.59:15
Free kick taken by Michael Bostwick.59:15 Booking
Booking The referee shows Callum Reilly a yellow card for unsporting behaviour.58:55
Callum Reilly concedes a free kick for a foul on Mark Little.58:11
The assistant referee signals for offside against Dwight Gayle. Free kick taken by Jack Butland.57:59
Peter Lovenkrands is flagged offside by the assistant referee. Kane Ferdinand takes the indirect free kick.57:14
The referee blows for offside against Dwight Gayle. Jack Butland takes the indirect free kick.54:44
Unfair challenge on Curtis Davies by Dwight Gayle results in a free kick. Jack Butland restarts play with the free kick.52:01
Nathaniel Mendez-Laing delivers the ball.51:05
Mark Little takes a shot. Steven Caldwell gets a block in. Lee Tomlin takes a outswinging corner from the right by-line played to the near post, clearance made by Nikola Zigic.49:16
The ball is crossed by Christopher Burke, Peter Lovenkrands has a headed effort at goal from close range which goes wide left of the target.48:11
A cross is delivered by Peter Lovenkrands, clearance by Michael Bostwick. Paul Caddis produces a cross, clearance by Lee Tomlin.45:01
The referee gets the second half started.45:00 +1:19 Half time
Half Time The whistle is blown to end the first half.43:49
Free kick awarded for an unfair challenge on Steven Caldwell by Dwight Gayle. Steven Caldwell takes the free kick.43:00
Michael Bostwick takes a shot. Comfortable save by Jack Butland.40:34
Foul by Mitch Hancox on Nathaniel Mendez-Laing, free kick awarded. Grant McCann delivers the ball from the free kick left-footed from right wing, clearance made by Jonathan Spector. Michael Bostwick takes a shot. Save by Jack Butland.39:25
Wade Elliott produces a cross, Shot from close range by Peter Lovenkrands misses to the right of the goal.38:00
Callum Reilly takes a shot.34:27
Christopher Burke takes a shot. Save made by Robert Olejnik.33:58
Christopher Burke provided the assist for the goal.33:58 Goal scored
Goal! - Nikola Zigic - Peterboro 0 - 1 Birmingham Nikola Zigic finds the back of the net with a goal from close in to the bottom left corner of the goal. Peterborough 0-1 Birmingham.32:11
Peter Lovenkrands takes a shot. Robert Olejnik makes a comfortable save.30:51
A cross is delivered by Christopher Burke, clearance made by Michael Bostwick.30:16
The ball is swung over by Mitch Hancox, Tommy Rowe makes a clearance.30:08
Christopher Burke produces a cross.29:48
Centre by Paul Caddis, Michael Bostwick manages to make a clearance.28:51
The ball is sent over by Mitch Hancox, clearance by Michael Bostwick.28:41
A cross is delivered by Jonathan Spector, clearance by Michael Bostwick.28:23
A cross is delivered by Peter Lovenkrands.26:44
Kane Ferdinand takes a shot. Save made by Jack Butland.24:00
The ball is sent over by Dwight Gayle, Kane Ferdinand produces a header from inside the area that goes over the bar.22:53
The offside flag is raised against Peter Lovenkrands. Indirect free kick taken by Robert Olejnik.21:04
Christopher Burke crosses the ball, Tommy Rowe manages to make a clearance.20:13
Free kick awarded for an unfair challenge on Christopher Burke by Tommy Rowe. Wade Elliott restarts play with the free kick.18:46
Tommy Rowe takes a shot. Save made by Jack Butland. Lee Tomlin takes a shot. Save made by Jack Butland. Outswinging corner taken by Grant McCann from the left by-line, clearance made by Nikola Zigic.17:47
A cross is delivered by Mitch Hancox, Michael Bostwick makes a clearance.17:33
Christopher Burke crosses the ball, save by Robert Olejnik.16:47
Free kick awarded for an unfair challenge on Curtis Davies by Lee Tomlin. Paul Caddis takes the free kick.16:00
Free kick awarded for a foul by Tommy Rowe on Jonathan Spector. Jack Butland takes the direct free kick.12:57
Jonathan Spector produces a cross.11:27
The ball is swung over by Nathaniel Mendez-Laing, clearance by Steven Caldwell. Corner taken left-footed by Grant McCann to the near post, Nikola Zigic manages to make a clearance.10:49
Tommy Rowe crosses the ball, clearance by Curtis Davies.10:06
Nikola Zigic challenges Grant McCann unfairly and gives away a free kick. Robert Olejnik takes the direct free kick.8:43
Free kick awarded for an unfair challenge on Nathaniel Mendez-Laing by Wade Elliott. Mark Little restarts play with the free kick.8:06
The ball is swung over by Christopher Burke.6:00
Centre by Christopher Burke, Nikola Zigic takes a shot. Robert Olejnik makes a save.5:36
The ball is delivered by Paul Caddis.4:21
Unfair challenge on Kane Ferdinand by Christopher Burke results in a free kick. Direct free kick taken by Grant McCann.2:04
Shot from just outside the area by Lee Tomlin misses to the left of the target.0:00
The referee starts the match.
Live data and text provided by our data suppliers