Niall Canavan opened the scoring before a Sam Winnall penalty and further goals from Jimmy Spencer and David Syers ensured United ended the evening in the play-off places.
Dale captain Oliver Lancashire and midfielder Jack O’Connell both saw red for the hosts in what could turn out to be a crucial three points in the League Two promotion race.
Caretaker managers Russ Wilcox and Tony Daws made one change to the side that beat Portsmouth on Saturday with Hakeeb Adelakun replacing Reuben Noble-Lazarus in the starting line-up for his first league start whilst the hosts also made one switch with Rhys Bennett coming in for Joe Rafferty.
The first opening of the game came after just a few minutes when Scunthorpe forward Deon Burton set up David Syers for a long range striking opportunity on the edge of the area but his right footed effort sailed well wide of the goal.
Dale had their first chance when Scott Hogan’s looping cross looked to be causing trouble for Sam Slocombe but the referee called for a foul by home forward Graham Cummins.
Iron winger Terry Hawkridge then tried his luck from distance but his fierce shot whistled just over.
The goal scoring attempts were beginning to come thick and fast and it was Hogan and Cummins who again linked up for Rochdale with the former crossing for the ex-Arsenal striker, who ultimately drew a fine save from Slocombe to keep the scores level.
Almost immediately after that, Scunthorpe had the ball in the back of the net as Andy Dawson’s long ball forward found Sam Winnall and he proceeded to lob his effort home only to see it ruled out for offside.
Midway through the half, Rochdale fullback Bennett cut onto his left foot and floated a curling cross towards goal that seemed innocuous on first glance but eventually forced Slocombe to tip the ball over the cross bar for a corner.
The Iron were then forced into a substitution as Dawson had to go off with what seemed to be a hip injury and he was replaced by Eddie Nolan at left back.
That change seemed to fluster United as the hosts began to enjoy the majority of the possession and had a goal ruled out themselves as the Scunthorpe defence couldn’t clear a ball into the box and Matt Lund found the net with a sweet strike into the bottom corner, only for it to be ruled out by the linesman’s flag.
The Iron then went up the other end and broke the deadlock as Hawkridge’s corner caused chaos in the Rochdale penalty area and Niall Canavan poked the ball home, from right under the goal line, to give United a 39th minute lead.
It had been a half of numerous chances but Canavan’s third goal of the season ensured United went into the break a goal to the good.
Rochdale were out early for the second period and made a purposeful start to it in their search for an equaliser as midfielder Lund hit one long range shot inches wide of Slocombe’s right hand post.
The hosts shuffled their pack with a couple of substitutions just shy of the hour mark but Scunthorpe were doing well to keep their opposition at bay.
Jimmy Spencer replaced Burton as United attempted to fresh things up but it was that man Lund who again went close as he headed just over from Ian Henderson’s corner.
Henderson then danced past Christian Ribeiro on the left wing before hitting a powerful effort that Slocombe did well to push away from goal as the game crept into the final 20 minutes of play.
Scunthorpe were given a helping hand in their quest to take the points as Dale captain Oliver Lancashire pulled Winnall down to the ground, just inside the United half and was sent off for a second bookable offence.
The Iron were making the extra man count with a succession of fine passing moves and went two goals ahead in the 74th minute.
Spencer latched onto Syers’ through ball and the Huddersfield loanee was fouled by Jack O’Connell in the penalty, presenting Winnall with the opportunity to double United’s lead.
He made no mistake as his calm spot kick sent the ‘keeper the wrong way to give Scunthorpe some breathing space.
O’Connell was sent off for the foul that lead to the penalty, meaning that the home side would have to play the remaining 15 minutes of the game with just nine players on the pitch.
Michael Rose attempted to pull a goal back instantly with a 30-yard free kick but his shot was straight at the gloves of Slocombe.
Ribeiro then ventured forward and unleashed a forceful drive that flew just over before Winnall played Syers in on goal but his effort was smothered by home ‘keeper Josh Lillis.
The Iron were beginning to completely dominate the game and went three goals up with five minutes to go as Noble-Lazarus’ low ball into the box was swept into the back of the net by Spencer, to score his first goal for the club.
Hawkridge went close with a long range half volley that Lillis did well to tip away and Scunthorpe added another goal as the game ticked past the 90 minute mark.
Noble-Lazarus was again the instigator as his low cross was instinctively slammed home by Syers to give United a four goal lead.
And that was how things stayed as referee Tony Harrington blew to signal the end of the game in what turned out to be a very convincing win for the Iron.
All focus will now switch to the home clash with Torquay United on Saturday.
Rochdale: Lillis, Bennett, Eastham, Lancashire, Tutte (Hery, 57), Hogan, Lund (Molyneux 76), O'Connell, Rose, Cummins (Done, 57), Henderson.
Substitutes not used: Thomson, Vincenti, Dicker, Bunney.
Scunthorpe United: Slocombe, Ribeiro, Mirfin, Canavan, Dawson (Nolan, 29), Hawkridge, McAllister, Syers, Adelakun (Noble-Lazarus, 82), Burton (Spencer, 65), Winnall.
Substitutes not used: Severn, Byrne, Waterfall, Iwelumo.