Second-half goals from Gareth Barry and Gabriel Agbonlahor gave Aston Villa victory over unlucky Rovers.
Blackburn drew first blood when Stephen Warnock exchanged passes with Benni McCarthy and fired home.
But Luke Young bundled in an equaliser from Nicky Shorey's cross and James Milner pulled the ball back for Barry to put Villa into the lead.
Agbonlahor raced onto Ashley Young's pass to make it 3-1 before Brett Emerton's injury-time free-kick.
Playing their third match in the space of six days, Villa looked jaded and will be delighted to have somehow scraped a victory that sees them move into fourth spot in the Premier League table.
Blackburn were the better side for much of the game and went ahead when Warnock rounded off a lovely team move to score his first goal of the season.
Andre Ooijer, McCarthy and Carlos Villanueva combined well and after Villanueva passed to Warnock, the left-back laid the ball in to McCarthy before collecting the South African's return and finishing coolly.
McCarthy only started the game because Roque Santa Cruz, who had been named in the starting line-up, suffered a calf injury in the pre-match warm-up.
It forced Rovers boss Paul Ince to make a last-minute change to his side, with McCarthy promoted from the substitutes' bench.
A win from nothing - O'Neill
Blackburn seemed untroubled by the late reshuffle and McCarthy took much of the credit for their deserved goal.
The opener prompted a response from Villa, whose captain Martin Laursen had a header from Luke Young's free-kick saved by keeper Paul Robinson and then headed Milner's right-wing cross wide of the target.
The home team looked out of sorts but Young's equaliser - his first goal for Villa - brought them back into the game.
Striker John Carew, again left on the bench after recently being fined for breaking a club curfew, was brought on at half-time in place of Stilian Petrov, who was struggling with a hamstring strain.
Carew's introduction seemed likely to galvanise Villa, but Blackburn still looked dangerous and went close when Emerton shot wide.
Warnock had a chance to restore Rovers' lead but skewed a shot well wide after being put through by Villanueva's fine pass.
That blunder was perhaps down to an earlier clash of heads between Reo-Coker and Warnock, who seemed to complain of double vision when he was substituted just after Villa went in front against the run of play.
Equaliser 'killed' us - Ince
Milner collected Ashley Young's pass, held off Ooijer and picked out Barry, who tapped home from three yards out.
That was tough on Blackburn, who continued to worry their opponents and were unlucky not to draw level.
Morten Gamst Pedersen's volley from Emerton's centre was well saved by Villa's former Rovers keeper Brad Friedel, and Emerton went close when he fired into the side netting.
The visitors' fate was sealed three minutes from the end, when Agbonlahor sprinted away from Christopher Samba and tucked the ball beyond Robinson.
Emerton found the corner of the net with a 25-yard free-kick, but it was no more than a consolation for Ince's men.
Aston Villa boss Martin O'Neill:
"We didn't play well at all. We never got going.
"We looked very jaded and I was absolutely delighted because we conjured up a win from absolutely nothing.
"We were second best in the first half. Blackburn passed the ball better than we did. When John Carew came on it did give us a bit more impetus."
Blackburn manager Paul Ince:
"We were comfortable in the first 45 minutes. We got the goal and never looked in any danger. Then we conceded a fortuitous goal from Villa's point of view.
"We had chance after chance in the first half and the second. We are playing some good stuff and the lads have shown they can come to places like Villa and control the game.
"I am encouraged, but try telling that to my players when they've lost the game. We feel we've dropped points against Bolton, Middlesbrough and Villa, and we can't keep doing that."
Aston Villa: Friedel, Luke Young, Shorey, Laursen, Cuellar, Barry, Milner, Petrov (Carew 46), Reo-Coker (Sidwell 83), Ashley Young, Agbonlahor (Harewood 90).
Subs Not Used: Guzan, Davies, Knight, Gardner.
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