It was Accrington who enjoyed all the first-half chances as Paul Mullin went close on three occasions and Andy Warrington in the Rotherham goal made two smart saves to keep the scores level.
He first saved well from a Jimmy Ryan free kick after 10 minutes and then made an even better save to keep out a 25-yard left-foot shot from Robert Grant.
Rotherham's only serious effort came from new boy Tom Pope who
poked a Nicky Law free-kick just wide of the target after 21 minutes.
But the half-time introduction of veteran Warne for Ryan Taylor sparked the home side into life.
Luke Joyce headed off the line from Nick Fenton, Kevin Ellison saw his goal-bound shot blocked and Alan Martin made two good saves to keep out a Warne shot and then an Ian Sharps header.
And it all came good for Rotherham in the 88th minute when Sharps crashed a shot against the crossbar and close-season signing Warne - back for his second spell with Rotherham - crashed home the loose ball.