After the blow of losing striker Chris O'Grady to a serious head injury the Millers fell behind to an early second half goal but they superbly displayed their fighting spirit by coming back to earn a well deserved victory.
United were first on to the attack in the fourth minute with Paul Hurst's cross finding Marc Newsham who fired wide while at the other end Hurst headed out a free kick. From the resulting corner former Miller Dave Artell headed just over the bar.
Danny Harrison and Marcus Bean combined for bean to flash a good cross in front of goal before a Steve Brogan saw Ian Sharps head the ball down to earn another flag kick.
After taking a pass from Newsham O'Grady had a shot deflected for a corner a minute after the keeper had saved a shot from the same player as the Millers dominated the proceedings.
Morecambe had a chance when they were awarded a free kick from 25 yards but Thompson fired his shot into the defensive wall and back came United again with a good deep cross from Dale Tonge that was caught by the keeper just under the bar.
Free kicks from Brogan and Peter Holmes brought no reward before there was a long hold up when O'Grady and keeper Joe Lewis clashed alarmingly. Both were flat out and play was held up for a long time before they were both replaced.
The first half closed with a superb Rotherham move that was stopped in the visiting penalty area but the deadlock was broken at the start of the second half when the visitors took the lead.
Andy Warrington had to turn a Thompson shot round the post and from the 47th minute corner Bentley headed home.
The Millers replied strongly and after Sharps had headed down a corner Brogan fed the ball back in for Holmes to have a shot blocked.
United made a double substitution on 64 minutes and that saw Ryan Cresswell play in an unusual position for him up front. Six minutes later it was all square when Artell pulled back Bean and Brogan stepped up to score confidently from the penalty spot.
Cresswell had a shot saved as did Yates with a 25 yarder while Harrison fired wide as Rotherham applied all the pressure. It paid off on 81 minutes when Brogan fed Newsham who went on a superb long run to set up the chance that Yates gratefully accepted for his first first team goal.
Newsham then fired wide after another fine move involving Yates and Tonge while the Millers made certain of the victory when they added a third goal on 88 minutes with Yates on hand to score from close range after an attempted clearance had skied up nicely into his path.
Almost immediately Yates provided a good cross that saw Newsham head just wide as the Millers recorded a well deserved victory.
Rotherham: Warrington, Tonge, Sharps, Coughlan, Hurst (Hudson 64), P. Holmes (Cresswell 64), Harrison, Bean, Brogan, O'Grady (Yates 41), Newsham. Subs: Annerson, Todd.
Morecambe: Lewis (Drench 41), Yates, Artell, Bentley, Stanley, Twiss, Baker, Thompson, Allen (Hunter 71), Blinkhorn (Newby 80), Adams. Subs: Howard, Sorvel.
Referee: Darren Deadman (Cambridgeshire).
