Reading climbed above Birmingham into second place in the Championship in the race for automatic promotion.
Birmingham slide to third after home defeat
Reading climbed above Birmingham into second place in the Championship in the race for automatic promotion back to the Premier League.
Goals from Noel Hunt, Kevin Doyle and Kalifa Cisse condemned Blues to a second successive defeat and saw Alex McLeish's men slide to third in the table.
Kevin Phillips had cancelled out Hunt's opener with a spectacular second-half drive, but Steve Coppell's men were full value for their victory.
The match was held up briefly in the early stages with Franck Queudrue and Hunt both requiring treatment after a nasty clash of heads as they challenged for a cross into the box, with both players able to continue.
Hunt appeared to have suffered no ill-effects from the incident and gave the Royals the lead in the 13th minute with a superbly-executed free-kick.
James McFadden was penalised for a challenge on the Irishman on the edge of his own box and Hunt stepped up to clip a clever effort over the wall and into the corner of the net beyond the despairing dive of Maik Taylor.
Coppell's men almost doubled their advantage with their next attack with Doyle breaking down the left and crossing to the far side of the box where James Henry drilled the ball back in, but no-one could get the crucial touch in front of goal.
Doyle then acrobatically volleyed into Taylor's arms from 12 yards out before Henry drilled a shot narrowly wide after being allowed to advance to the edge of the Birmingham area.
Purpose
Goalscorer Hunt was then forced out of the action as his earlier clash with Queudrue had left him with blurred vision which was getting progressively worse as the match went on, Shane Long coming on in his place in the 27th minute.
Birmingham offered little as an attacking threat in the first half with Phillips and Cameron Jerome unable to test Adam Federici and were sent out early for the second period with the words of McLeish no doubt ringing in their ears.
Blues started the second half with more purpose, and were back on level terms on the hour mark thanks to a stunning strike from Phillips, who took full advantage of some hesitant play from the visitors.
Lee Carsley robbed Cisse as he dwelt on the ball in the Birmingham half, with Phillips then collecting possession and advancing unchecked as Michael Duberry and his fellow defenders backed off before unleashing a 20-yard effort which arrowed beyond Federici.
But Reading regained the lead just six minutes later when Stephen Hunt curled a free-kick into box where Doyle was left completely unmarked to glance a clever header across Taylor and into the far corner for his 16th league goal of the season.
Birmingham responded with Radhi Jaidi's goal-bound header from a Sebastian Larsson corner striking Jerome and bouncing to safety, before Phillips drew an excellent save from Federici after his strike partner had pulled the ball back.
And it was the Royals who scored a killer third eight minutes from the end with Doyle producing a great cross from the right flank which picked out Cisse at the far post to plant a powerful header beyond Taylor.
Jerome had the chance to reduce the deficit with four minutes to go when he was released by substitute Quincy Owusu-Abeyie, but clipped his shot back across Federici and beyond the post.
