A late Andre Gray strike fired the Clarets back into the automatic promotion places with a fine 2-1 win at St. Andrew’s Stadium.
Wins for rivals Brighton and Middlesbrough before Burnley kicked off at St Andrews had seen Sean Dyche’s men drop to third.
But they roared out a warning to both after Gray struck his 24th goal of the campaign 13 minutes from time after Jacques Maghoma’s second half header had cancelled out George Boyd’s first half strike.
And with Burnley hosting Midlesbrough in a summit meeting at Turf Moor on Tuesday, with a chance to go top, the scene is set for a thrilling end to the season.
Dyche made two changes from last week’s 1-0 victory over Leeds United, with David Jones and Sam Vokes (groin) missing out of the starting eleven.
Dean Marney returned in midfield while Ashley Barnes made his first start since the last game of the 2014/15 season.
Two early half-chances from the hosts failed to trouble Tom Heaton, as Ryan Shotton’s 10th minute header was glanced wide, ahead of a Maghoma strike from 20-yards which sailed aimlessly over.
Midway through the half another Maghoma chance went begging, as he fired wide from 12 yards following s slick City counter.
Moments later the Clarets had their first effort of the game.
Heaton’s kick-forward was headed out to Scott Arfield, and the newly capped Canadian ambitiously went for goal with a 25-yard volley which just dipped over the crossbar.
However on the half hour mark the visitors struck first.
Matthew Lowton’s low cross from the right was only half-cleared to the edge of the box, and a fine strike from Boyd found the bottom right corner!
Former Sheffield United and Doncaster winger Cotterill was then denied twice moments before the break by two-stunning saves from Heaton, the first coming from a free kick.
Inbetween, the Clarets were denied a chance to double their lead from the spot after a blatant handball from Maikel Kieftenbeld, whose flailing arm from a Jones corner cleared the ball, but incredibly wasn’t spotted by referee Mark Heywood.
Then, on the stroke of half time another strike from Cotterill looked destined for the equaliser, but a brilliant save from Burnley’s captain ensured the Clarets remained ahead at the break.
The Clarets made a change at half time, with David Jones replacing Joey Barton, who suffered a tight calf.
And the Clarets could have doubled their advantage straight from the restart.
Gray outmuscled Shotton, drove forward into the box, but the league’s top scorer was denied by Adam Legzdins as he went for the near post.
The resulting corner found Jones at the edge of the box after good build-up play from Boyd, and with his first touch of the game, Jones saw his low effort fly wide of the far post.
The midfielder then brilliantly found Barnes with a flick-on outside of the box, but the returning striker’s half-volley could only find the side-netting.
And moments after almost doubling the advantage, the Clarets were pegged back!
Jon Toral, who scored in the fixture at Turf Moor, struck from distance, forcing Heaton to parry out to his right. However, Maghoma was lurking and his diving header brought the game level.
The hosts were then inches away from turning the game on its head.
Cotterill’s corner from the right found Jonathan Grounds rising in the box, and the defender’s thumping header rattled out to safety off the crossbar!
Former City midfielder Lloyd Dyer was introduced to make his Burnley debut, and the winger made an instant impact.
Burnley countered, with Dyer bursting down the left and pulling the ball back to Marney, whose strike from 20-yards was scuffed wide.
However with 13 minutes to play the Clarets grabbed the all-important second goal!
Neat play from Dyer found Boyd on the left wing and his pinpoint cross evaded Marney and the Birmingham defence, finding Gray criminally unmarked to fire home at the far post
A tense remaining 10 minutes slowly ticked by, before, in stoppage time, Dyer gathered in the centre of the park, turned the already-carded Toral and was fouled, leaving Birmingham down to 10 men as the Clarets cruised home.
Burnley: Heaton; Lowton, Keane, Mee, Ward; Arfield (Dyer 60), Marney, Barton (Jones 45), Boyd; Gray (Tarkowski 89), Barnes.
Subs: Robinson, Darikwa, Taylor, Hennings
Goals: Boyd 30’, Gray 77’
Yellow: Ward 36’, Boyd 71’, Marney 84’
Birmingham: Legzdins, Caddis, Morrison, Shotton, Grounds, Kieftenbeld, Davis, Cotterill (Fabbrini 79), Toral, Maghoma (Lafferty 79), Donaldson
Subs: Gleeson, Vaughan, Solomon-Otabor, Spector, Kuszczak
Yellow: Toral 33’
RED: Toral 93’
Referee: Mr. M Heywood