Match ends, Birmingham City 1, Brentford 0.
Birmingham City moved clear of the relegation zone to damage Brentford's play-off push at St Andrew's.
Blues led when Clayton Donaldson's header at goal was deflected into his own net by James Tarkowski.
Brentford, who stay seventh in the table, should have levelled before the break but Jonathan Douglas headed over.
Gary Rowett's side had midfielder Stephen Gleeson sent off late on for a stamp on Alex Pritchard, but the visitors could not capitalise.
Blues are now up to 13th, 11 points clear of the relegation zone after a timely win which arrived hours after the Football League was assured that the Midlands club have the funds to complete the season.
Birmingham's parent company, based in the Far East, is in the hands of receivers Ernst and Young, who have told the Football League that their appointment should not be considered as an "insolvency event".
If the League viewed it as such, a 10-point penalty could be handed out, raising the prospect of a relegation scrap.
A run of nine games without a win before kick-off had pulled the 2011 League Cup winners closer to the bottom three but Tarkowski's own goal proved enough to earn a return to winning ways.
Blues had conceded eight goals in defeats by Brighton and Ipswich before Brentford's visit but defended resolutely.
Aside from Douglas's wasteful header from Jon Toral's cross, Mark Warburton's side barely threatened.
Birmingham's teenage winger Demarai Gray missed the game's only other clear-cut opening, firing over with the goal at his mercy just after the hour.
He tried to make amends late on, shooting wide from a tight angle as Birmingham closed out victory despite Gleeson's late show of ill-discipline.
Birmingham City manager Gary Rowett:
"This is the biggest win of our season. It was an absolute crucial win. To get it against a Brentford side who are going really well under manager Mark Warburton was very important.
"I thought we defended brilliantly against Brentford and I thought that with a little more composure and a little more quality and a tab more ruthless play we could have added to the single goal.
"Clayton Donaldson was brilliant against his old team. He has been monumental this season and when we play that lone striking role he plays it as well as anyone. He physically imposes himself on the game and is such a great worker for the team.
Brentford manager Mark Warburton:
"It was a good move and a good ball into the middle. It is testament to Douglas that he gets into that area. He gets forward and has scored some vital goals for us and I have no problem with him as nine times out of 10 he scores from that position.
"We lacked a bit of quality and were not quite at our best. We had a lot of possession but lacked care on the final ball. But this is a tough league. There are a lot of points to be played for over the coming weeks.
"We have a chance on Tuesday against Huddersfield to deliver a strong performance and remain in the mix."
- 31CaddisBooked at 90mins
- 8GleesonBooked at 87mins
- 11CotterillSubstituted forNovakat 90'minutes
- 22ShinnieSubstituted forReillyat 90'minutes
- 33GraySubstituted forDyerat 76'minutes
- 10OdubajoSubstituted forMcCormackat 76'minutes
- 20DiagouragaSubstituted forJudgeat 60'minutes
- 23JotaSubstituted forBidwellat 60'minutes
- Darren Bond
- Shots on Target
Second Half ends, Birmingham City 1, Brentford 0.
Paul Caddis (Birmingham City) is shown the yellow card.
Attempt missed. Alan Judge (Brentford) right footed shot from outside the box is high and wide to the right following a corner.
Corner, Brentford. Conceded by Callum Reilly.
Substitution, Birmingham City. Lee Novak replaces David Cotterill.
Substitution, Birmingham City. Callum Reilly replaces Andrew Shinnie.
Attempt missed. Jon-Miquel Toral (Brentford) header from the centre of the box is too high. Assisted by Alex Pritchard with a cross following a corner.
Corner, Brentford. Conceded by Jonathan Spector.
Attempt blocked. Alex Pritchard (Brentford) right footed shot from outside the box is blocked.
Stephen Gleeson (Birmingham City) is shown the red card.
Alex Pritchard (Brentford) wins a free kick in the attacking half.
Foul by Stephen Gleeson (Birmingham City).
Attempt blocked. Andrew Shinnie (Birmingham City) left footed shot from the right side of the box is blocked. Assisted by Clayton Donaldson.
Attempt missed. Alan Judge (Brentford) right footed shot from outside the box is close, but misses to the left. Assisted by Alex Pritchard.
Corner, Brentford. Conceded by David Cotterill.
Andre Gray (Brentford) wins a free kick on the right wing.
Foul by Rob Kiernan (Birmingham City).
Substitution, Birmingham City. Lloyd Dyer replaces Demarai Gray.
Substitution, Brentford. Alan McCormack replaces Moses Odubajo because of an injury.