Birmingham recorded their fifth straight win as they coasted to a 2-0 triumph at Rotherham.
The big-spending Blues won the battle of last season's Championship teams thanks to two first-half goals.
Birmingham took a 14th-minute lead when Tomoki Iwata seized on a blocked shot from Jay Stansfield and lashed into the bottom corner from the edge of the box.
They doubled their lead in the 22nd minute when Stansfield latched onto an incisive pass from Willum Willumsson and lobbed Dillon Phillips.
Emil Hansson threatened a third with a bending shot which Phillips had to tip away from goal.
Rotherham had a big chance to get back in the game when Jamie McCart's header had to be pushed away by Bailey Peacock-Farrell.
Substitute Scott Wright could have made the scoreline more resounding when he was teed up by Stansfield but his shot was blocked by McCart.
Alex Cochrane almost got the visitors' third when he rattled the bar with a late free-kick.
Report supplied by PA Media.
