The hosts were two goals ahead inside 21 minutes after fine finishes from John O’Sullivan and Jamie McClaren, and the deficit might have been greater in a one-sided first-half.
United rallied after the break and passed up a handful of presentable opportunities, before McClaren seemingly put the outcome beyond doubt by stabbing home his second goal.
Joe Rothwell reprised his spectacular shooting of last week’s draw against Middlesbrough with another rasping long-range effort and Tom Lawrence also curled in a stunning effort, but it was too little, too late for the Reds.
In a keenly-contested game littered with fouls and cautions, Blackburn adapted better, while United struggled to find a passing rhythm and often caused their own problems.
Luke Hendrie managed to clear the danger on 10 minutes, after Tyler Blackett’s blind back-pass had been intercepted, but there was no reprieve when the Reds failed to play their way out of defence five minutes later.
Declan Dalley only managed to scuff his clearance to the edge of the area, but O’Sullivan’s emphatic finish hurtled unstoppably inside Joe Coll’s far post.
The United goalkeeper was similarly helpless six minutes later, when Curtis Haley’s looping cross was superbly redirected inside the far post by McClaren’s arcing header.
Rovers continued to menace, while Sam Byrne headed off-target and fired straight at home goalkeeper Chris Dilo with the Reds’ best openings of