The England striker glanced home a header eight minutes after Danny Welbeck's deflected 11th-minute shot had put the Black Cats in front to claim his 10th goal of the season and his first in six games.
Bent could easily have grabbed a second-half hat-trick and was guilty of a glaring 62nd-minute miss from just three yards, although former Sunderland striker El-Hadji Diouf had earlier contrived to fire over from even closer.
But substitute Asamoah Gyan sealed a victory which took Sunderland to 30 points for the season with a third at the death to provide the perfect antidote to their wastefulness against the Seasiders in front of a crowd of 36,242.
For manager Steve Bruce, there was also a taste of vicarious revenge on behalf of close friend Sam Allardyce following his unceremonious dismissal by Rovers.
It had been a difficult week for Bruce, who was without seven players for the Boxing Day trip to Manchester United, and then saw his side create a hatful of chances against Blackpool and fail to take any of them as they slipped to a 2-0 home defeat, their first of their league campaign and just the second in 2010.
Add to that his dismay at turning 50 yesterday, and the former United defender could have been forgiven for wishing to see the back of an eventful seven days.
In the circumstances, his players could hardly have responded anymore positively as they took the game by the scruff of the neck from the off and threatened to have it won by the break.
Welbeck, Bent and record signing Gyan uncharacteristically fired blanks on Tuesday, but they made amends in fine style.
Injuries to Nedum Onuoha, Lee Cattermole and Gyan meant Bruce had little option to reshuffle his side, and his decision to restore Kieran Richardson at left-back and move Phil Bardsley to the right to allow Ahmed Elmohamady to resume his preferred midfield role proved a masterstroke.
The Egypt international made life intensely difficult for full-back Martin Olsson, and it was his ability to deliver the ball into the danger area which was responsible for both first-half goals.
Rovers skipper Ryan Nelsen got his head to Elmohamady's 11th-minute cross and then attempted to block Welbeck's shot after he had controlled on his chest and volleyed towards goal.
However, the New Zealand international only succeeded in deflecting the ball past wrong-footed keeper Mark Bunn to hand Sunderland an early lead.
Blackburn's plight became increasingly desperate within eight minutes when Bent got in front of defender Grant Hanley to head Elmohamady's cross into the bottom corner.
But for all their dominance, the home side should have been pegged back 11 minutes before the break when former Sunderland striker El-Hadji Diouf was guilty of a glaring miss.
Bruce's men were aggrieved to concede a free-kick as David Dunn ducked into David Meyler's challenge, and their mood might have darkened from the resulting set-piece.
Morten Gamst Pedersen curled an inviting free-kick to the far post, where Diouf met it unopposed but somehow contrived to smash it over the bar from barely two yards.
Welbeck clipped the top of the crossbar with a delicate 37th-minute chip with the Black Cats looking to kill the game off, but keeper Craig Gordon was relieved to see Dunn's 44th-minute effort from distance fly just wide after he had cut inside onto his left foot.
Rovers boss Steve Kean withdrew Hanley at the break and replaced him with striker Benjani Mwaruwari as Brett Emerton moved back into defence with his team having abandoned the 4-5-1 formation with which they had started the game.
That gave them a more adventurous look and they might have capitalised nine minutes after the restart when El-Hadji Diouf did well to get in a cross from the right and Mame Biram Diouf headed it just wide.
Dunn went close seconds later with a dipping volley as the Black Cats came under sustained pressure for the first time in the game, but the game should have been over with 62 minutes gone.
Steed Malbranque and Richardson carved Rovers open down the left and when the full-back crossed for the unmarked Bent in the middle, only to see him miss the target from just three yards.
Bent passed up another glorious opportunity two minutes later when he shot wide after Gael Givet had failed to cut out a Malbranque cross, and drilled a 75th-minute left-foot effort wide, while Jordan Henderson hit the bar three minutes later.
But Gyan made sure a minute from time to wrap up a regulation victory with a fine individual goal.