A packed out Aggborough saw Kidderminster match their opponents from a higher level for an hour.
But the Championship punished a defensive error when Wes Thomas scored in the first half.
The striker fired Blues ahead at the start of the season half before substitute Clayton Donaldson bagged a third.
“We did enjoy it apart from three sloppy errors but we’ve been through that with the boys and they’ve taken that on board,” said Creighton.
“The first goal came from a corner we’ve never practised in our lives and Craig Reid took some stick for that one.
“All-in-all it was a great work out but there were a few things to work on but we can start doing that now we’re settling down.
“Fitness-wise we’re good but Birmingham were a little brighter in the mind. You can accept that because they’re a Championship side but legs-wise we look about right.
“We need to work on a bit of shape and we’re two weeks away from the start of the league and we can start looking at the nitty gritty bits now.”
Creighton remains hopeful that Marvin Johnson will recovered from a jarred knee after being taken off as a precaution.
The wideman had looked lively and tested Darren Randolph before being replaced by Ahmed Obeng.
Obeng looked bright and had a goal in the second half ruled out for offside.
Creighton said: “Marvin’s taken a bit of a knock and he was taken off as a precaution, it’s a pre-season friendly so there’s no point him carrying on and causing more damage.
“It look okay and hopefully he will be okay for Shrewsbury on Tuesday.”