On-loan Nouha Dicko started things off after nine minutes after Alex Revell flicked on, then Kieran Agard made it two-nil after 23 minutes.
Ben Pringle capped a fine solo run by firing home after 35 minutes and although Cody McDonald put the frighteners on Rotherham with a 65th-minute goal for the visitors, on-loan debutant James Tavernier restored the Millers' three-goal advantage in the 75th minute.
"Some of the passing, some of the one-to-one touches, it really was stunning at times, "said Evans.
"And James Tavernier deserved his goal in the second half because he was denied 10 minutes earlier by an absolutely stunning save. But his was one of many outstanding performances. I am as pleased with my squad at this time as I could be and it will be helped when some of our injured players get back.
"When we get them back it will be a bit like last season with real options in the run-in. We are not quite there yet, but we will have some good options and we will be a far better team in the second half of the season.
"In terms of end product, I think our first-half performance was the best of any of the teams I have managed. That was a performance that was absolutely stunning. And against a team and a manager I have the utmost respect for.
"The goals made it a complete performance in the first half and we could have scored two or three more. We tore them to shreds."
Source: PA