Rovers booked their place into the semi-finals of the Carling Cup after defeating Chelsea in a penalty shootout.
In a game that saw two hours of high drama it was Rovers who prevailed after Paul Robinson saved Gael Kakuta's spot-kick to send them through to a last four match against Aston Villa.
It had started brightly for Rovers when Nikola Kalinić fired Rovers in front after just nine minutes.
In an end-to-end encounter Salomon Kalou missed the chance to level but he headed wide when in front of goal.
With Rovers leading at the break Carlos Ancelotti made a triple change, Didier Drogba one of those introduced.
That had the desired effect with the Ivorean heading home just two minutes after his introduction, then Salomon Kalou went through on goal to give the visitors the lead.
Rovers looked shellshocked with Kalou missing a gilt-edged chance to stretch their league further.
But under Sam Allardyce and Neil McDonald, they are made of sterner stuff and when a centre from Brett Emerton went through the legs of Hilario with Kalinić claiming a touch, the scores were level once again.
An injury to Kalou meant the visitors had to play out the final 15 minutes of the 90 with just ten men but Rovers couldn't take advantage, Junior Hoilett blazing wide when through on goal.
Extra-time arrived and just three minutes in Rovers were back in front after Hoilett was felled by Zhirkov. The ever reliable Benni McCarthy sent Hilario the wrong way.
With a goal and a man advantage Rovers looked to see the game out, but deep into two additional minutes after 120 having been played, a free-kick from Florent Malouda was missed by Robinson and Paulo Ferreira took full advantage to fire into the empty net.
That meant Rovers had to pick themselves up after the heartache of that last minute leveller to prepare for the penalty kicks.
They were given an early boost when Ryan Nelsen won to toss to have the penalties taken towards the Blackburn End. Benni McCarthy blasted in the first spot-kick.
Chelsea captain Michael Ballack stepped up for his side's first kick, he hit the ball to Robinson's left but the Rovers number one dived brilliantly to tip the ball onto the post.
Emerton dispatched his kick with aplomb whilst Drogba cheekily chipped Robinson, Grella made no mistake before Malouda sent Robinson the wrong way.
However with Rovers leading 3-2 Kalinić saw his kick saved, and it was 3-3 when Yury Zhirkov just saw his spot-kick sneak past Robinson.
Junior Hoilett, the young man who missed a glorious chance to win the game in regulation time stepped up to take Rovers' fifth kick, and how did he handle the pressure? By blasting the ball into the top right corner of the goal, a superb penalty.
That meant a sudden death penalty for Chelsea and for the young attacker making all the headlines for the wrong reasons - Gael Kakuta. The Frenchman drove his effort straight into the arms of Robinson and Rovers were through.
The euphoria was there for all to see, the players didn't know whether to celebrate or to collapse to the ground in relief.
The draw had actually been made whilst both sides were preparing to enter extra-time. Rovers reward for winning sees them face Aston Villa.
ROVERS: Robinson, Salgado, Samba, Nelsen (c), Chimbonda, Emerton, Nzonzi (sub van Heerden 90 mins), Pedersen (sub Grella 62 mins), McCarthy, Kalinić, Roberts (sub Hoilett 70 mins).
Subs not used: Brown (GK), Givet, Diouf, Jones.
CHELSEA: Hilario, Ivanovic, J. Cole (sub Kakuta 46 mins), Mikel, Ballack (c), Malouda, Zhirkov, Ferreira, Deco (sub Drogba 46 mins), Kalou, Belletti (sub Bruma 46 mins).
Subs not used: Turnbull (GK), Matic, Hutchinson, Borini.
Booked: Grella (Rovers), Bruma (Chelsea)