Rotherham skipper Richard Wood has given the home side a 1-0 half-time lead over Town at the New York Stadium.
Town boss Paul Lambert named an unchanged XI for the third game in a row for the first time this season.
Will Norris was again in goal behind a back three of skipper Luke Chambers, James Wilson and Luke Woolfenden. Luke Garbutt and Gwion Edwards were the wing-backs.
In midfield, Emyr Huws and Flynn Downes were behind Alan Judge with Will Keane and Kayden Jackson the strikers. There was one change on the bench with Myles Kenlock coming in for Josh Earl.
There was a late change of referee with Antony Coggins taking over from scheduled official Marc Edwards.
Matt Crooks, who scored both goals in the Millers’ 2-0 defeat of the Blues at Portman Road in October, nodded an early header wide in a scruffy first couple of minutes.
The home side, whose direct approach was starting to pay dividends, came within an inch or two of going in front in the 11th minute when Town were caught daydreaming as Daniel Barlaser played a quick freekick into Kyle Vassell on the right of the box and the striker’s well-struck shot cannoned off the underside of the bar.
Eventually, the ball ended up behind with referee Coggins awarding a corner, wrongly according to the Town players, and from the corner Michael Smith headed straight at Norris.
Rotherham threatened again in the 18th minute when a superb cross-field pass found Hakeeb Adelakun breaking into the area on the left. However, the full-back’s first touch took the ball a little wide and Norris was able to block his attempt at goal. Following the corner, Crooks headed wide.
Town, in blue shorts, had had a frustrating first 20 minutes with a number of arguable freekick decisions going against them in what had been a very stop-start opening, while they had been unable to impose themselves on the game and get the ball down and pass it around in the manner which has become familiar in the last few games against a physical and determined Rotherham side.
As the clock passed the 25-minute mark there was a round of applause in tribute to Matlock Town player Jordan Sinnott, who was killed at the weekend. Millers midfield Crooks was wearing a black armband in tribute to his friend and former Huddersfield team-mate.
The game continued in much the same manner as it moved past the half-hour mark. Much of the match was being played in the Town half, but without Norris being particularly threatened, while the Blues looked to get the ball forward quickly to strikers Jackson and Keane but without success.
On 37 Crooks was shown the first yellow card of the game for hauling back Keane after the striker had found some space to break into in the Millers half.
Four minutes later, Rotherham, who had been a threat from set pieces all half, took the lead from a corner on the left.
Smith headed a deep ball played beyond the far post towards Norris, Vassell toed it against the keeper’s knee, sending it into the air and Millers’ skipper Wood nodded into the roof of the net from a matter of inches. Norris protested that he had been fouled but looked to have little case.
A minute after the goal Huws was booked for a frustrated foul on Vassell before the board was raised announcing two additional minutes.
Town won a corner in the additional time following a break forward by Downes but the flag-kick eventually came to nothing.
The home side deserved their lead at the break with Town having shown little of their recent form during the first half. The players’ frustration at their display, and a number of the refereeing decisions, was evident.
Rotherham might have gone ahead earlier through Vassell with the Blues never passing with the fluency of recent weeks and all too often looking to hit their strike pairing with early balls over the top, a tactic which had yielded no success.
Town will have to be much better after the break if they’re to avoid suffering their first League One defeat of 2020.
Rotherham: Iversen, Thompson, Ihiekwe, Wood (c), Mattock, Ogbene, Barlaser, Crooks, Adelakun, Vassell, Smith. Subs: Bilboe, Olosunde, MacDonald, Lindsay, Wiles, Lamy, Ladapo.
Town: Norris, Chambers (c), Wilson, Woolfenden, Edwards, Downes, Huws, Garbutt, Judge, Keane, Jackson. Subs: Holy, Kenlock, Skuse, Norwood, Nolan, Bishop, Sears. Referee: Antony Coggins (Oxfordshire).