Hull brought Birmingham’s proud 29-game unbeaten home league record to an end with a dramatic 3-2 victory.
In a feisty encounter, the Tigers became the first team to emerge from St Andrew’s with all three points since Cardiff in April last year.
Sergej Jakirovic’s side were helped when home defender Jack Robinson was dismissed after picking up his second yellow card for dissent just before the hour.
And both clubs are likely to be asked to explain themselves following a four-minute stoppage towards the end of the first-half after both benches and players were embroiled an ugly melee.
The afternoon kicked-off with a shock 11th-minute goal for the visitors when Oli McBurnie played Kyle Joseph through.
The forward managed to flick the ball past James Beadle only for Robinson to get his feet in a muddle and help it into the net as he was running towards goal.
Birmingham got a deserved equaliser in the 27th minute when Jay Stansfield struck his fifth goal of the season.
Patrick Roberts caused a problem with a tricky run from the right before picking out Paik Seung-Ho whose shot was parried to the England Under-21 striker who finished.
With three minutes of the half remaining, both sets of players and benches came together, causing a four-minute stoppage.
The trouble flared after Joseph appeared to catch Roberts close to the dug-outs . That incensed home boss Chris Davies who became embroiled in an exchange with the Hull bench.
That then spilled over to a fracas involving almost every player on the pitch – including the two goalkeepers who chose to involve themselves on the halfway line as matters almost spilled over.
Security staff tried to pull the feuding players apart and the match was eventually re-started by referee Ruebyn Ricardo who brandished four yellow cards to a variety of players and associated staff.
The visitors took a decisive lead during first-half stoppage time when David Akintola found Lewis Coyle on the overlap.
Hull’s skipper lifted the ball into the area where Regan Slater placed his header beyond James Beadle to restore their lead.
Birmingham’s chances of protecting their unbeaten record took a knock just before the hour when, following a Marc Leonard shot that flew over the bar, Robinson picked up two yellow cards in quick succession for dissent.
That left the hosts with the game to chase – and they peppered Ivor Pandur’s goal with chances – although leaving themselves open at the other end.
Beadle, who went up for a late corner, should have drawn the hosts level but missed a header from point-blank range before Joe Gelhardt added a third for Hull deep into stoppage time.
However, the events of the afternoon were not finished. Lyndon Dykes was shoved over in the dying seconds, allowing Stansfield to reduce the arrears before the final whistle sparked scenes of jubilation for Hull’s supporters.
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