Jay Stansfield grabbed a late winner to fire Birmingham top of the Championship with a 2-1 win over 10-man Swansea.
Stansfield struck three minutes from time after a Christoph Klarer own goal had cancelled out his first-half opener for the Blues.
Ryan Allsop saved Ross Stewart's early Swansea penalty after the referee felt Jenson Seelt had been shoved over by Alex Cochrane from the first corner of the match.
Goncalo Franco headed against the post as Swansea continued to dominate the early exchanges.
But the referee intervened again, this time sending off Marko Stamenic for a high challenge on Ethan Laird.
Birmingham quickly capitalised on their advantage as they opened the scoring on the half hour mark through Stansfield.
Max Bird was played in behind the defence and was able to play a simple square pass to Stansfield, who produced a clinical finish.
Stansfield soon had a chance to double the lead but Lawrence Vigouroux stood strong and made an excellent point blank save.
Just before the half-time whistle, the Swansea keeper was forced into action again, making an impressive double save.
With Swansea down to 10, Birmingham were able to maintain control of the game during the second half.
There were loud appeals for a penalty when Laird looked like he was tripped in the box but the full-back only earned a yellow card for simulation.
Despite the home side's dominance in possession, the Swans remained in the game and took their chance to equalise from a corner through Klarer's unfortunate own goal.
The Birmingham crowd were becoming increasingly frustrated by their team's lack of urgency.
Meanwhile, Swansea's substitutes continued to make an impression.
It took a set piece at the other end for Birmingham to finally get their noses in front again. Once again it was Stansfield taking centre stage.
The ball fell to him in the box after a ricochet and Vigouroux could do nothing about his powerful deflected strike.
Birmingham manager Chris Davies:
"It's great to be at the summit and to have touched the summit of this league with everything we've been through and the whole journey.
"I was really disappointed with the penalty. I've watched it back so many times and I just can't understand why the referee's given that. I mean it's incredible, the lad's just thrown himself on the floor."
Swansea head coach Vitor Matos:
"You need to play to win no matter what situation you are in. That's the real heart and soul of a good team. Find ways to compete and find ways to stay competitive, whatever the context is.
"Unfortunately, sometimes life is like that, you get knocks. It's up to us to find ways to bounce back again. When I look to the performance, I have no doubt that that will happen."
