The second-placed Blues, who boast by far the biggest budget in the division, dominated the contest, and their 2-0 victory was their fifth straight win in League One.
The Millers had started with five defenders in a bid to curb the visitors’ attack but found themselves 2-0 down within 22 minutes and reverted to their usual four-man backline at the interval.
With summer signing Sean Raggett back in the side after injury as one of three centre-halves, it came down to a choice between the two other centre-backs, Humphreys and Jamie McCart, as to who came off.
“Jamie McCart, you just couldn’t take him out when you go to a four because he’s been really good for us,” Evans said.
The boss was pleased with the contribution of Raggett – a regular starter n Portsmouth’s third-tier title campaign last term – who had been sidelined since the first week of the season by a knee twist.
“For him to come in and play like that was commendable,” he said. “I thought he did really well. He was the one in the opposition box looking to create and win a header and be powerful.”
Rotherham brought on Joe Powell at the break to bolster a midfield that had been outnumbered in the first half.
Birmingham, whose summer recruitment included spending £15 million on striker Jay Stansfield and breaking the League One transfer record, didn’t score in the second period but remained in control of the game.
The loss dropped the Millers to 21st spot and they now face trips to Shrewsbury Town and Cambridge United in their next two fixtures.
“We were well beaten this afternoon,” said Evans in his after-match press conference in the New York media suite. “Birmingham are a £25-million team with wages to match.
“I’m not coming here to make any form of excuses. We’ve learned lots of lessons today.
“We’ll go away and work hard on the training ground and we’ve got two tough away games to come. We’ll regroup and try to get ready for them.”
