After 2 defeats on the bounce, The Millers was desperate to answer some questions and get thier promotion bid back on track, and that they did with ease.
Michael Smith’s early goal had the Millers ahead at half-time before David Ball’s strike on the hour-mark and Richie Towell’s well-worked third capped off a fine performance from the Millers, who remain in the top four.
Rotherham were on top from the word go and took the lead after 18 minutes when the home side failed to deal with Will Vaulks’ long free-kick and Smith was left unmarked to shoot into the bottom corner.
Only a superb save by Richard O’Donnell prevented Towell from adding a quick second before he also denied Ball.
Northampton had to wait until 55 minutes for their first shot when Hildeberto Pereira’s low drive was held by Marek Rodak, but Rotherham were soon two to the good.
Ball found the net from 12 yards after the Cobblers defence had failed to clear and Rotherham’s victory was completed by Towell, who finished off a fine move by placing Anthony Forde’s pass into the corner.