Dexter Blackstock's double earned Nottingham Forest a shock win and consigned Birmingham City to a first home Championship defeat this season.
Blackstock poked home the opener from Garath McCleary's centre.
The home side drew level when Chris Burke shot home with his left foot after good work by Marlon King.
But Blackstock secured a victory which keeps Forest three points clear of the relegation zone when he controlled and converted another McCleary cross.
Neither side created much before Blackstock's opener, although Forest then began to get on top as Andy Reid blazed over the bar and Adlene Guedioura sent a long-range strike wide.
The Blues improved in the second half and, after a spell of pressure, winger Burke curled in a superb equaliser from King's pass.
Forest responded and McCleary found space on the right to send in a teasing ball which Blackstock flicked over his shoulder and then fired into the top-right of goal from 12 yards.
The hosts pressed for another equaliser, with David Murphy shooting over, King forcing a parry from keeper Lee Camp and Nathan Redmond missing the target from 25 yards.
Guy Moussi went close at the other end while Birmingham almost made it 2-2 when Keith Fahey hit the bar and centre-half Curtis Davies sent the follow-up effort off target.
Birmingham City 01 Myhill 03 Murphy 04 Caldwell 23 Spector 24 Davies 07 Burke 11 Townsend (Redmond - 82' ) 12 Mutch 18 Fahey 09 King 19 Zigic (Huseklepp - 68' ) Substitutes 13 Doyle 05 Pablo 10 Huseklepp 14 Gomis 22 Redmond Nottingham Forest 01 Camp 04 Chambers Booked 05 Higginbotham (Lynch - 22' ) 16 Gunter 26 Elokobi 11 Reid (Wootton - 90' ) 19 Moussi 22 Guedioura 12 McCleary (Anderson - 85' ) 20 Tudgay 23 Blackstock Substitutes 21 Smith 02 Wootton 33 Lynch 07 Anderson 10 McGugan