Birmingham celebrated their takeover in style with a 4-2 win as Rotherham came bearing gifts in the Sky Bet Championship at St Andrew's.
Blues were finally taken over by Trillion Trophy Asia on Monday after protracted negotiations and they got their new era off to winning start against the struggling Millers.
Goals from Michael Morrison, Lukas Jutkiewicz, Jacques Maghoma and David Cotterill did it for Blues, but they were far from their best, with three of the goals coming from defensive blunders.
Still Gary Rowett's men were able to extend their unbeaten home run to five games and optimism around St Andrew's will be high.
Rotherham, who have lost all seven of their away games conceding 23 goals in the process, were far better in attack than they were in defence and goals from Danny Ward and Jon Taylor kept them in it.
But six defeats on the bounce and already six points adrift of safety, boss Alan Stubbs must be fearing for his job.
Rowett will have no doubt wanted to impress his new bosses and his side made the perfect start.
After Jutkiewicz had put two headers just wide they deservedly took the lead in the 15th minute. The Millers failed to clear a corner and when Jonathan Grounds sent the ball back in Morrison rose highest to send the ball looping over Lee Camp.
Rotherham had been threatening down the right and that is where they made their 31st-minute equaliser. Substitute Greg Halford cut inside and fed a nice ball into the area, which Jake Forster-Caskey dummied, allowing Ward to sweep home into the bottom corner.
Having done the hard work of getting level, Stubbs' men criminally allowed Birmingham to regain their lead just four minutes later.
Left-back Darnell Fisher had all the time in the world to clear the ball, but he fluffed his header, allowing Cotterill to cross for Jutkiewicz to steer his header past Camp.
Blues were the beneficiaries of even more inept defending eight minutes later as they took a 3-1 lead.
Halford, a Birmingham loanee last season, was bundled off the ball far too easily and Maghoma then ran 20 yards and sent his 20-yard shot into the bottom corner.
The Millers, utterly hopeless in defence, did at least have more about them going forward and they got back in it in the 56th minute through Taylor, who fired a low effort passed Adam Legzdins from Ward's knockdown.
That gave them some impetus and Izzy Brown tested the handling of Legzdins, who also kept out Lee Frecklington's header.
Rotherham continued to look more likely but were unable to create anything clear-cut and Birmingham made it safe when Cotterill converted from the spot after more poor defending saw sub Che Adams felled by Camp in the final 10 minutes.