Ben Wiles' superb strike and a second goal from Shane Ferguson helped Rotherham leapfrog Plymouth and go top of League One following their emphatic 2-0 victory at Ipswich.
It extended the visitor's unbeaten run to 12 games and left Ipswich tumbling down the league.
Town keeper Christian Walton flung himself across goal to divert a shot from Rotherham midfielder Jamie Lindsay and Wiles struck for the visitors after 24 minutes when he made ground down the left and hit a left-footed shot past Walton from just outside the penalty area.
Lee Evans' free-kick from 25 yards saw Rotherham keeper Viktor Johansson flying across the goal as the ball went just over the bar but Rotherham extended their lead in the 59th minute when Ferguson was on hand to put the ball in the net after Freddie Ladapo's shot was blocked.
Rotherham striker Michael Smith nearly made it three when his header went just over the bar following a cross by Ferguson as the visitor's ran out thoroughly deserved winners.