Leicester 0 Birmingham 2
Leicester had skipper Matt Elliott and goalkeeper Ian Walker sent off - plus manager Micky Adams banished from the dug-out - as Steve Bruce's side gained only their second Premiership win in the last 10 games.
Elliott faces a three-match ban for violent conduct after catching Blues midfielder David Dunn with his forearm in an aerial challenge in the 37th minute.
Adams was so upset by the decision - and referee Mike Riley's overall performance - that he remonstrated with the official on the pitch before half-time and was also given his marching orders. Leicester were enjoying the better of the exchanges and looked confident. Leicester boss Adams had to be moved away from Riley by stewards and was subsequently banished from the dug-out.
Leicester were reduced to nine men when Walker was sent off. The keeper came out of his area and saw his clearance bounce off Forssell and then Thatcher back towards him and instinctively he grabbed the ball.
Then in the 60th minute Walker inadvertently handled the ball outside his area after his clearance had been charged down and was also given a red card.
To cap an afternoon of misery for the home side goals from Clinton Morrison - in his first league start for eight months - and Mikael Forssell ended their five-game unbeaten run.
Robbie Savage had received a standing ovation on his return to City but once the game started he was booed every time he touched the ball. Savage incurred the wrath of the home crowd for a challenge on Andrew Impey but escaped a caution.
Riley harshly booked James Scowcroft after 32 minutes after a challenge on Jamie Clapham and then yellow-carded Damien Johnson after he had left his foot in on Ben Thatcher.
However the game exploded into life in the 37th minute when Elliott was red-carded after catching Dunn in the face with his forearm in a touchline aerial challenge. Then five minutes later Blues were given the lead via the recalled Morrison in his first start since March when he suffered a dislocated shoulder.
Clapham provided the low cross from the left of the penalty area and Morrison was first to react to steer a shot wide of Ian Walker. The game was bubbling over and Stephen Clemence was booked for a late tackle on Izzet and at half-time incensed
The Foxes made a half-time switch with Les Ferdinand replaced by John Curtis in a tactical switch. Scowcroft moved up front, Impey into midfield and Curtis into a back three in a 3-4-2 formation. Tempers were still frayed and Paul Dickov was yellow-carded for a late challenge on Clemence.
Then after 61 minutes Leicester were reduced to nine men when Walker was sent off. The keeper came out of his area and saw his clearance bounce off Forssell and then Thatcher back towards him and instinctively he grabbed the ball.
It left Riley with no option but to send the England player to the dressing room. Savage curled the resulting free-kick just over the bar but he was to then set up the second Blues goal for Forssell after 65 minutes. He sent over a right-wing cross and Forssell had time to pick his spot before heading powerfully past replacement keeper Danny Coyne.