In a physical encounter at Madejski Stadium, visitors Birmingham City took all three points through two first half goals from Clayton Donaldson and Ryan Shotton - ending the Royals' unbeaten league run at home in 2016.
Donaldson headed the Blues into the lead when he thundered home a David Cotterill cross to give Gary Rowett's men a second minute advantage and they deserved their second goal, scored by Ryan Shotton after Ali Al Habsi had palmed clear a Caddis free kick. There was to be no repeat of the midweek comeback this time as City put men behind the ball to hold on to all three points.
Royals' boss Brian McDermott named an unchanged side to the team that was victorious over Nottingham Forest in mid-week, with Garath McCleary and Deniss Rakels both fit enough to return to the bench for the home side
On a showery afternoon at Madejski Stadium it was the visitors who got off to a flying start when powerful striker Clayton Donaldson headed home after David Cotterill had attacked the hosts down the right.
Reading looked for a quick response and had a chance to level the scores just a few minutes later through a Norwood corner, the midfielder's whipped delivery found Lucas Piazon in the centre but his flicked effort cleared the Birmingham crossbar.
The visitors doubled there lead however just before the half hour when Ryan Shotton profited from a Paul Caddis free kick. The set piece was firmly struck and Royals keeper Ali Al Habsi parried the effort away, but the ball fell to Shotton who made no mistake from close range to make it 2-0.
Reading pushed forward, looking to get themselves back in the game winning a series of corners, that were stoutly defended by the visiting side and Kermorgant came close to pulling one back only for the offside flag to deny him as his header sqirmed through the clutches of Adam Legzdins and possibly over the line. But the remainder of the half was predominantly played out in midfield with the score still at 2-0 heading into the break.
Half Time:Reading 0-2 Birmingham City
In a tight start to the second half there were few opportunities but the Royals were enjoying the majority of possession. The first oppurtunity fell to Kermorgant who steered his header goalwards but it was well saved by Legzdins from close range.
Matej Vydra had been introduced at the break and Reading were playing better football, albeit creating little in front of goal as City put numbers behind the ball to hold onto their advantage. The Royals continued to press with Jordan Obita looking threatening down the left-hand side, whipping a number of dangerous deliveries to the back post.
The next opening came for centre-half Jake Cooper when he headed over from an Oliver Norwood free-kick; Norwood's floated delivery from the right-hand side picked out the Royals Academy graduate who couldn't send his effort on target.
In what was turning into a second half of few chances, Reading continued to boss the ball, but were continually rebuffed by a stubborn the Birmingham defence. The Royals used the width through substitutes Ola John and Garath McCleary to try and break down the Birmingham rearguard and Kermorgant again went close this time from a McCleary cross - the ball was floated to the far post and Kermorgant rose well forcing a save from the Birmingham keeper.
In the closing moments Ola John saw his low effort fly just wide of the Birmingham post after cutting in from the left wing onto his right foot. His shot from range had the goalkeeper scrambling, but bounced just wide of the visitors' upright. Williams arrowed wide late on, but there was to be no way through and Reading's unbeaten streak in the league at home came to a disappointing end.
Full time:Reading 0-2 Birmingham City
Reading: Al-Habsi, Gunter (McCleary 63), McShane, Norwood, Obita, Piazon (Vydra HT), Quinn, Williams, Kermorgant, Cox (John 72), Cooper
Unused Subs: Bond, Taylor, Hector, Rakels.
Yellow: McShane, Cooper, Kermorgant.
Birmingham City: Legzdins, Grounds, Kieftenbeld, Gleeson, Cotterill (Soloman-Otabor 72), Davis, Morrison, Caddis, Shotton, Lafferty (Maghoma 72), Donaldson.
Unused Subs: Kuszczak, Toral, Spector, Fabbrini, Vaughan.
Yellow: Donaldson, Morrison.