Blackburn's quick-fire double sinks Birmingham
Two goals in three first half minutes were the difference as Blackburn produced an excellent display to defeat play-off hopefuls Birmingham 2-0 in the Sky Bet Championship.
Tony Watt's smart turn and finish in the 20th minute for his first Rovers league goal set the hosts on their way and Danny Graham's composed strike three minutes later ultimately left Birmingham with too much to do.
Gary Rowett was furious his team did not get a penalty just before that, though that should not mask an impressive display by Paul Lambert's men.
The visitors showed some life in the second half and hit the woodwork but got going too late in the game.
The win was Blackburn's fourth on the bounce at Ewood Park in the Championship - the first time they have managed that for six years.
Defeat means Birmingham, who have slipped further away from the top six, have now won just once in the last 10 on the road, and have a solitary away victory in 2016.
Lambert refreshed his side after the narrow derby defeat to Burnley by bringing the fit-again Corry Evans back in along with Watt for Hope Akpan and Matt Grimes respectively.
Rowett named an unchanged side after Birmingham's impressive defeat of Hull.
The Rovers boss asked his team to impose themselves following recent impressive performances and they certainly did that by taking a deserved 20th minute lead.
Evans lofted the ball into the box and Shane Duffy headed to Watt who wriggled free of two defenders before poking under Tomasz Kuszczak.
The game's major talking point came three minutes later as Clayton Donaldson went down under a Ben Marshall challenge with just Jason Steele to beat and Rowett was apoplectic that referee Stuart Attwell waved away penalty appeals.
His ire worsened as Steele's quick ball released Graham and the striker did the rest, evading a challenge before coolly slotting home his third in Blackburn colours.
Birmingham only had Stephen Gleeson's injury time effort that was easily saved by Steele to show in a poor first half.
Blackburn continued to look the more accomplished after the break and Kuszczak had to be alert to grab Watt's free header before producing a smart low stop to keep out a ferocious Graham drive as Blackburn countered.
Despite showing little attacking threat, Birmingham twice went agonisingly close to scoring on the hour mark, when Jacques Maghoma saw his weak effort cleared by Grant Hanley, though the ball bounced off Elliott Bennett before falling fortuitously behind.
The corner eventually fell to Jonathan Grounds whose powerful drive thudded off the woodwork, before Watt flashed wide at the other end.
Steele produced a flying save from Diego Fabbrini towards the end but Blackburn ran out deserved winners.