El-Hadji Diouf's second half header earned Rovers a point against title-chasing Chelsea at Ewood Park.
The former Senegal international arrived at the back post to head home a centre from Michel Salgado in the 70th minute.
It was only what Rovers deserved who had picked themselves up from the disappointment of going behind so early when Didier Drogba netted after just 6 minutes. Then Salomon Kalou headed narrowly over as Carlo Ancelotti's side started strongly.
But Rovers rallied, Ross Turnbull saved Morten Gamst Pedersen's free-kick, whilst Yury Zhirkov headed off the line from Samba's flick.
Pedersen then wasted the chance to level minutes before Diouf headed home, but at the death Jason Brown saved well to stop Drogba.
The point sees Rovers go back to 12th, whilst at the same time blowing the title chase wide open.
Sam Allardyce made four changes from the White Hart Lane outing the previous week. With Paul Robinson out injured it meant a first league start of the season for Jason Brown, whilst Keith Andrews and El-Hadji Diouf were preferred to Brett Emerton and Pascal Chimbonda who dropped to the bench.
With Gael Givet and Ryan Nelsen absent through injury it meant a league debut for 18-year-old defender Phil Jones who was given the task of marking Drogba, Anelka and co.
Within six minutes of the opening the visitors found themselves in front with a move of simplicity and class. Nicolas Anelka skipping past two challenges on the right before cutting in a teeing up Didier Drogba to net his 28th goal of the season.
Two minutes later a Frank Lampard corner kick found the head of Salomon Kalou, but his bullet header flew inches over the bar.
At that point it looked like Chelsea could run riot, but to their credit Rovers regrouped and started to impose themselves on the title chasers. A fine move involving David Dunn and Nikola Kalinić was brought to a halt by a lunge from Chelsea defender Alex, and although Morten Gamst Pedersen fired in the resulting free-kick with venom, Ross Turnbull was able to claim stop the ball, although he couldn't stop it from going behind for a corner.
From that corner Keith Andrews met El-Hadji Diouf's centre, but couldn't keep the ball down.
Martin Olsson blocked an Alex shot through a crowded area, whilst at the other end Pedersen blazed over after Samba had headed Andrews' centre down.
Showing no signs of nerves on his debut, Jones drew a standing ovation past the half hour with two fantastic pieces of tackling, storming from defence, the centre half first tackled Lampard before doing the same with Malouda. Much to the delight of the home fans.
Florent Malouda showed quick feet to get past Samba just before half time, but Jason Brown palmed away his left-footed strike.
On the stroke of half-tie Chelsea were forced into a change as Ivanovic was replaced by Yury Zhirkov.
Into the second half and it was the home side who were quick out of the blocks. A Morten Gamst Pedersen long throw saw Chelsea struggle to cope, Chris Samba got the flick but Zhirkov was on hand to head the ball off the line.
Morten Gamst Pedersen fired well wide when urged to shoot, but Frank Lampard was mere inches away with a 35 yard strike that saw Jason Brown scrambling across his area.
A good opportunity was then spurned a great chance to level when Morten Gamst Pedersen chested down an Nzonzi cross field pass. The Norwegian raced towards the near post but his effort flew across the area.
But sixty seconds later the Blackburn End net was bulging. There seemed little on as Brett Emerton saw his route down the right blocked, he passed back to Michel Salgado who crossed from the right over to the back post where El-Hadji Diouf arrived to head Rovers back on level terms.
That set up a pulsating final twenty minutes, but whilst Rovers couldn't carve out any openings themselves, they prevented title chasing Chelsea from creating too much in the way of opportunities.
When one did come their way they found Jason Brown in the way as from a Deco corner kick Didier Drogba let fly on the volley, but the stand-in goalkeeper made a superb save.
Four additional minutes lead to some nervy moments, but Rovers held their own to claim an impressive point.
Debutant Phil Jones was given the man-of-the-match award for his strong display at the heart of the Rovers defence and at the final whistle he was given a huge hug by his captain Chris Samba.
ROVERS: Brown, Salgado, Samba (c), Jones, Olsson, Diouf, Andrews, Nzonzi (sub Hoilett 90 mins), Pedersen, Dunn (sub Emerton 56 mins), Kalinić (sub Roberts 63 mins).
Subs not used: Bunn (GK), Jacobsen, Linganzi, Chimbonda.
CHELSEA: Turnbull, Ivanovic (sub Zhirkov 45 mins), Lampard, Drogba, Mikel, Malouda, Ferreira, Kalou (sub Deco 74 mins), Terry (c), Alex, Anelka (sub Sturridge 90 mins).
Subs not used: Sebek (GK), J. Cole, Matic, Bruma.
Booked: Zhirkov (Chelsea)