After an early scare, when Danny Hylton's shot was bravely blocked by Guy Branston, Rotherham took the lead after 14 minutes. Shots goalkeeper Ross Worner spilled Gareth Evans' 30-yard free-kick and Lewis Grabban was left with a simple tap in.
The Millers could have doubled their lead in the 27th minute but Worner made up for his earlier mistake with a brilliant save to keep out a Branston header and followed up with a second save to deny Evans.
Jermaine McGlashan had a great chance to level for the visitors a minute later, but he shot into the side netting and Rotherham went on to double their advantage four minutes before the break.
Chris Holroyd's glancing header from Evans' free kick was just enough to take the ball wide of Worner's dive and into the top corner.
And things got worse for the visitors 10 minutes after the break when Worner received a straight red card after he raced out of his area and clattered straight into Alex Revell. With no keeper on the bench, Hylton mad way and midfielder Jamie Collins came off the bench to take over between the sticks.
However, Collins proved his worth with a smart save to deny Holroyd but it mattered little as the Millers comfortably saw the game out.
Source: DSG