Chris Burke's stunning first-half strike gave Birmingham City their first away win of the season at Championship leaders Brighton.
Blues boss Lee Clark was undoubtedly looking for a positive response from his side following their 5-0 defeat at Barnsley last time out.
He got just that as Burke's 25-yard strike in the 27th minute was enough to give the visitors all three points.
Despite the defeat, Brighton remain top of the table on goal difference.
Brighton had won their last five games in the Championship, but were sluggish from the outset against Birmingham.
The first chance of the game came in the 23rd minute as Stephen Dobbie's half volley from just outside the area flew past Jack Butland's left-hand post.
Birmingham opened the scoring four minutes later. Gordon Greer's clearing header only went as far as Burke, who smashed an unstoppable volley past the stranded Tomasz Kuszczak.
Brighton improved after the break but still struggled to carve out a clear-cut chance.
Dean Hammond failed to make a meaningful connection with a Dobbie cross when well placed, while a David Lopez free kick was headed away by the Birmingham defence.
Five minutes of stoppage time was shown at the end of the 90 minutes but Brighton could not break down a resolute Birmingham defence and suffered their first home defeat of the season.
Brighton & Hove Albion boss Gus Poyet told bbc Sussex:
"You have to give credit to the way they defended. They were more compact and more solid, we had so many chances to create something, that we didn't, and we only have ourselves to blame.
"The problem was they scored first, so it was always a hurry and looking for that special something and we didn't have.
"We need special players to produce and offensive players to give something special and they tried hard but we didn't produce."
Birmingham City manager Lee Clark:
"The goal was worthy of winning any game. "Everyone was hurting last weekend as we didn't perform to the demands made, but the players to a man have responded magnificently.
"It was an awful 72 hours but we needed a game plan coming to a place like Brighton and we simply couldn't dwell on the Barnsley game.
"There is a lot of ability in the Brighton team and they have several potential match winners and in my opinion they are right on the verge of progressing to the next level."
Live Text Commentary
Full Time The referee signals the end of the game.90:00 +4:22
The ball is sent over by Inigo Calderon, Curtis Davies makes a clearance.90:00 +1:12
Free kick awarded for a foul by Wade Elliott on Kazenga LuaLua. Free kick taken by Moreno David Lopez.90:00 +0:06
The referee blows for offside. Jack Butland takes the free kick.89:32
Corner taken by Gary Dicker played to the near post, Steven Caldwell manages to make a clearance.88:27
A cross is delivered by Marlon King, clearance made by Gordon Greer.86:48
Paul Robinson takes the direct free kick.86:48 Substitution
Substitution Marlon King comes on in place of Leroy Lita.86:48
Free kick awarded for an unfair challenge on Leroy Lita by Liam Bridcutt.86:04
Free kick awarded for an unfair challenge on Gary Dicker by Jonathan Spector. Free kick crossed right-footed by Moreno David Lopez from left wing, Leroy Lita makes a clearance.84:56
Free kick awarded for an unfair challenge on Kazenga LuaLua by Wade Elliott. Free kick taken by Wayne Bridge.83:44
Free kick awarded for a foul by Jonathan Spector on Kazenga LuaLua. Liam Bridcutt restarts play with the free kick.82:26
Direct effort from the free kick comes in from Wade Elliott.82:26 Booking
Booking Gordon Greer booked for dissent.82:17
Gordon Greer concedes a free kick for a foul on Nathan Redmond.80:57 Substitution
Substitution Will Packwood goes off and Hayden Mullins comes on.79:09
Unfair challenge on Liam Bridcutt by Jonathan Spector results in a free kick. Wayne Bridge takes the free kick.78:35
Ashley Barnes challenges Paul Robinson unfairly and gives away a free kick. Jack Butland takes the free kick.77:58
Kazenga LuaLua delivers the ball, Jack Butland makes a save.75:57
Corner taken by Moreno David Lopez played to the near post, Close range header by Ashley Barnes goes over the bar.
Stephen Dobbie takes a shot. Blocked by Keith Fahey.72:22
Ashley Barnes is caught offside. Jack Butland takes the indirect free kick.71:10
Indirect free kick taken by Jack Butland.71:10 Substitution
Substitution Kazenga LuaLua replaces Will Buckley.71:10
The assistant referee signals for offside against Will Buckley.70:14
The ball is sent over by Will Buckley, save by Jack Butland.68:45 Substitution
Substitution Nathan Redmond on for Peter Lovenkrands.68:21
The ball is crossed by Stephen Dobbie, save made by Jack Butland.67:59
Will Buckley sends in a cross, clearance made by Curtis Davies.67:01
Paul Robinson concedes a free kick for a foul on Ashley Barnes. Inigo Calderon takes the free kick.66:32
Direct free kick taken by Wayne Bridge.66:32 Booking
Booking The referee books Wade Elliott for unsporting behaviour.66:20
Wayne Bridge fouled by Wade Elliott, the ref awards a free kick.64:59
Corner taken by Moreno David Lopez, clearance made by Curtis Davies.63:22
Outswinging corner taken right-footed by Will Buckley from the right by-line, clearance made by Curtis Davies.63:05
The ball is crossed by Wayne Bridge.61:38
The ball is delivered by Will Buckley, clearance by Wade Elliott.60:24 Substitution
Substitution Moreno David Lopez replaces Adam El-Abd.58:41
Corner taken by Gary Dicker, clearance by Steven Caldwell.57:49
Foul by Liam Bridcutt on Wade Elliott, free kick awarded. Free kick taken by Keith Fahey.56:21
Inswinging corner taken by Gary Dicker from the left by-line, clearance made by Curtis Davies. Inswinging corner taken from the left by-line by Gary Dicker.53:09
Stephen Dobbie takes a shot. Save by Jack Butland.50:05
Centre by Wayne Bridge, Headed effort from inside the area by Stephen Dobbie misses to the right of the goal.48:39
Dean Hammond concedes a free kick for a foul on Wade Elliott. Jack Butland restarts play with the free kick.47:33
Corner taken short by Will Buckley.45:25
Will Buckley is flagged offside by the assistant referee. Jack Butland restarts play with the free kick.45:01
The referee blows his whistle to start the second half.45:00 +2:05 Half time
Half Time The first half comes to an end.45:00 +1:36
Will Buckley is flagged offside by the assistant referee. Jack Butland takes the indirect free kick.44:55
Jonathan Spector crosses the ball, save by Tomasz Kuszczak.43:46
Unfair challenge on Wade Elliott by Adam El-Abd results in a free kick. Free kick taken by Jack Butland.42:41
A cross is delivered by Will Buckley, save by Jack Butland. Corner taken right-footed by Gary Dicker.39:16
Keith Fahey fouled by Liam Bridcutt, the ref awards a free kick. Keith Fahey takes the direct free kick.38:23
Curtis Davies concedes a free kick for a foul on Stephen Dobbie. Free kick taken by Liam Bridcutt.38:07
A cross is delivered by Christopher Burke, save by Tomasz Kuszczak.37:22
The assistant referee signals for offside against Will Buckley. Free kick taken by Jack Butland.35:52
Will Buckley sends in a cross, clearance by Will Packwood.34:24
Free kick awarded for a foul by Adam El-Abd on Leroy Lita. Paul Robinson takes the free kick.34:04
Wayne Bridge delivers the ball, clearance by Steven Caldwell.32:03
The offside flag is raised against Dean Hammond. Jack Butland takes the indirect free kick.29:21
Stephen Dobbie produces a cross, Adam El-Abd takes a shot. Jack Butland makes a comfortable save. Leroy Lita takes a shot. Save by Tomasz Kuszczak. Leroy Lita concedes a free kick for a foul on Liam Bridcutt. Liam Bridcutt restarts play with the free kick.27:25
Centre by Wayne Bridge, Inigo Calderon takes the chance to get an effort at goal. Wade Elliott gets a block in. Corner from the right by-line taken by Gary Dicker, save by Jack Butland. Short corner worked by Stephen Dobbie.26:12 Goal scored
Goal! - Christopher Burke - Brighton 0 - 1 Birmingham Christopher Burke gets on the score sheet with a goal from outside the penalty area to the top left corner of the goal. Brighton 0-1 Birmingham.25:51
Wade Elliott fouled by Gary Dicker, the ref awards a free kick. Direct free kick taken by Will Packwood.25:08
The ball is crossed by Wayne Bridge, clearance by Paul Robinson.24:01
Christopher Burke produces a cross, Inigo Calderon manages to make a clearance.22:53
Stephen Dobbie has an effort at goal from just outside the box which goes wide of the right-hand post.20:53
Will Buckley concedes a free kick for a foul on Paul Robinson. Direct free kick taken by Paul Robinson.18:08
The offside flag is raised against Will Buckley. Indirect free kick taken by Jack Butland.16:41
Will Buckley is caught offside. Jack Butland takes the indirect free kick.14:35
Foul by Wade Elliott on Liam Bridcutt, free kick awarded. Free kick taken by Gordon Greer.8:23
The assistant referee signals for offside against Ashley Barnes. Indirect free kick taken by Jack Butland.4:53
Will Buckley produces a cross.0:12
Gary Dicker takes the outswinging corner, Inigo Calderon takes a shot. Christopher Burke gets a block in.0:00
The referee starts the match.
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