Cardiff City reached the League Cup semi-finals for the first time since 1966 on an emotional night following the death of Wales manager Gary Speed.
Kenny Miller put Cardiff ahead on 19 minutes after Aron Gunnarsson's pass pierced the static Rovers defence.
Miller was denied a second by Scott Dann's goal-line clearance, before Rovers captain David Dunn went close.
Filip Kiss headed the second after the break and Cardiff held on to heap more pressure on Blackburn boss Steve Kean.
Blackburn, propping up the Premier League table, managed just one effort on target after conceding the second and struggled to generate any semblance of concerted pressure on their Championship hosts.
Poignant scenes preceded the match as respect was paid to Wales manager Gary Speed, whose body was found on Sunday.
During a minute's applause, both managers were joined by Football Association of Wales chief executive Jonathan Ford in laying wreaths on a Welsh flag at the side of the pitch.
A minute's silence followed, before the cry of "there's only one Gary Speed" echoed around the stadium - the scene of Speed's last game 17 days ago.
Under the cloud of such tragic circumstances, the match took its time to ignite, with Blackburn enjoying the better start in possession.
The first corner after 18 minutes brought the first moment of danger as Grant Hanley's header was blocked on its way to Cardiff's bottom corner.
But barely two minutes later, the predatory Miller struck for the Bluebirds in their first meaningful attack.
Gunnarsson robbed the dithering Morten Gamst Pedersen in midfield, and his instinctive pass sent Miller clear through the heart of the Blackburn defence.
Miller's touch took him towards the left side of the box, but his low left-footed shot went through the legs of the on-rushing Mark Bunn for his sixth goal of the season.
Only inches prevented Miller from doubling Cardiff's lead five minutes later.
The Scotland international beat Hanley on the byline, dummied his way past Bunn but Dann blocked his shot on the line.
A goalmouth scramble ensued, but again the visitors managed to clear.
Cardiff grew in stature from then, their pressing game giving Blackburn no time to find any midfield rhythm.
Rovers captain Dunn, one of five changes in the side from Saturday's defeat to Stoke, had blazed over from the edge of the box in the opening stages, and he finally called Tom Heaton into action in the Cardiff goal when he connected well with a 30-yard volley.
Kean, battling for his Blackburn future, sent his side out early for the second half, but he was soon staring at a two-goal deficit.
Peter Whittingham's deep corner eluded Bunn's grasp, and Kiss was only a yard out when he deflected the ball in after Anthony Gerrard headed across the face of goal.
Both players claimed the goal, but replays clearly showed Kiss having the final touch.
Cardiff's movement continued to trouble Rovers, with Gunnarsson shooting wide, before setting up Miller again, who this time fired wildly over.
Whittingham's influence grew as the home side controlled midfield, and right-back Kevin McNaughton then epitomised Cardiff's energy as his 30-yard run ended with a driven shot across Bunn's goal.
After conceding the second, David Goodwillie soon forced a fine save from Heaton but that proved to be Blackburn's only second-half effort on target.
They came close in the closing stages, but Dann's header and substitute Ruben Rochina's curler from the edge of the box went inches wide.
Kean sent on Ayegbeni Yakubu and Jason Roberts in the final stages in hope of a late rally, but the faultless home defence held firm to extend Cardiff's unbeaten run to eight games.