It was a long time coming, but Matthew Etherington's superb 69th-minute free-kick finally ground down the Millers to give toiling West Ham the valuable win that lifted them up into fourth place in The Championship.
After a busy week in the transfer market, Alan Pardew had handed out four home debuts to Calum Davenport, Chris Powell, Malky Mackay and Carl Fletcher as the new-look Hammers sought to follow up Saturday's hard-fought victory at Sheffield United with another three points.
But coming up against yet more Yorkshire grit, the Eastenders found the going tough as bottom-placed, winless Rotherham defended stoutly, forcing frustrated West Ham into long-range pot shots during a low-key first half.
First, Teddy Sheringham sent a dipping 20-yard free-kick inches over the bar, before Tomas Repka and then Nigel Reo-Coker saw efforts from similar distance foiled by keeper Michael Pollitt.
Luke Chadwick also twice went close to breaking the deadlock but, in the end, it was Rotherham who came closest to taking an interval lead when the sliding Paolo Vernazza emerged at the far post to steer Robbie Stockdale's 39th-minute deep, low centre into the sidenetting.
As the Millers and their 155 fans enjoyed their half-time tea safe in the knowledge that they were still well and truly in the contest, Pardew would have been justified in hurling a few cups around the dressing room in a bid to wake his promotion-seeking side from their slumber.
Whatever the Hammers boss did, though, it certainly had some effect as West Ham emerged for the second half with a much greater sense of urgency.
Indeed, Marlon Harewood's breathtaking, early touchline surge deserved more than Sheringham's careless penalty spot lay-off, while Fletcher climaxed a clever juggle with a low, angled 15-yarder that sizzled wide.
It was always going to take something special to break the Rotherham resistance and when Darren Garner upended Harewood 20 yards out, Etherington stepped up to curl a fabulous curling free-kick around the defensive wall and beyond the outstretched right hand of the flying Pollitt.
And as West Ham claimed victory there was to be yet more agony for Ronnie Moore's troubled troops when Richie Barker was stretchered off ten minutes from time following Davenport's robust challenge.