Rotherham started much sharper and Rovers' stopper Thimothee Lo-Tutala had to be alert early on to race out and smother Martin Sherif's tentative effort after he'd beaten the offside trap.
That aside, the first 25 minutes was shorn of any real quality - that was until Rovers broke the deadlock in emphatic style. James Maxwell put in a peach of a cross from the left flank and Owen Bailey met it with a perfectly timed header to continue his outstanding scoring run at the start of this season - it's now five goals in all competitions for the captain.
He then fired straight at Cammy Dawson as the hosts looked to add a second before half-time, whilst Glenn Middleton saw a speculative effort come back off the crossbar.
They were cursing the woodwork again just after the break when Tom Nixon's drive came back off the post. It was becoming a more open game and Rotherham's Ar'Jany Martha hit a sweet, dipping volley that Lo-Tutala did excellently to parry away.
The rest of the half was a gritty affair with chances at a premium: Middleton was denied by Dawson's legs and the visitors' best chance of pinching a point came when sub Jordan Hugill blazed wide in added time.
Here's our player ratings:
9. Jordan Gibson 7
Looked really sharp first half and buzzed about with intent before fading second half and being replaced by Ajayi for the last quarter. Photo: Howard Roe/AHPIX LTD
10. Billy Sharp 6
A tough day of it up against the Millers' three centre-halves. Not his game in all fairness with minimal involvement in front of goal. Photo: Howard Roe/AHPIX LTD
11. Glenn Middleton 7
In for Molyneux and deployed on the right. Struck the crossbar just before half-time and moved back to his more natural position on the left when Ajayi came on. Photo: Bruce Rollinson/AHPIX LTD
12. Ben Close 6
Good to see him get some rare league action. Made an important block on Powell's shot in the box late on. Photo: Howard Roe/AHPIX LTD