Four goals in 16 minutes put The Blues back on top of the Premier League, and put the pressure on Man Utd ahead of their trip to Anfield.
Frank Lampard bagged 2 goals to continue his return to form, and justify his preferred deeper midfield role, whilst Joe Cole made a sparkling return to the starting 11.
Cole nearly got Ancelotti’s side off to the perfect start inside the opening 30 seconds, finding himself unmarked 6 yards from goal, the England international could only head wide.
But this early attack was the sign of things to come, as Paul Robinson’s goal was peppered with efforts from distance.
The most notable of these chances was a crisp strike from Lampard that stayed gun-barrel straight and whistled past the post.
In the 20th minute the home side did make the break through and it all started from a rare Blackburn attack, with Chelsea hitting on the break.
The ball broke to Michael Ballack who then slipped in Nicolas Anelka down the left. The Frenchmen produced a perfectly weighted low cross for Didier Drogba to attack, but the Ivorian was beaten to it by Gael Givet, who turned it past his own keeper.
This could have opened the floodgates but to their credit Blackburn stuck to their task and like all sides under Sam Allardyce, where hard to break down.
A slick move across the penalty area involving Cole, Lampard and Anelka almost brought a second before halftime, but Robinson did well to block Anelka’s shot.
Drogba then hit a swerving 35 yarder that almost deceived the keeper, before Terry and Drogba again pulled fine saves out of the Robinson.
Throughout the first half Carlo Ancelotti had looked a frustrated man as his side wasted chances, and whatever he said during the interval clearly emphasised his annoyance, as Chelsea blew Rovers away in the second half.
Lampard got the ball rolling in the 48th minute, when a lovely turn and cutback from Drogba down the left channel ran to the number 8, who coolly fired home from 12 yards.
It was 3-0 soon after as the shoot on sight policy saw Michael Essien reap the rewards, his curling 30-yard strike too good to keep out.
Juliano Belletti was forced off on the hour with a stomach problem, but Chelsea didn’t break stride.
Just 4 minutes later Chelsea had a 4th, Didier Drogba brought down by Ryan Nelsen after powering into the area. Lampard did the honours from the spot.
And 5 minutes later Chelsea had their fifth. Michael Ballack whipping in a corner and Drogba out muscled Nelson to head home.
Joe Cole then returned to his showboating best, with stepovers and a scissorkick cross to get the home fans on their feet.
Another encouraging sight was the first team debut of young Dutchmen Jeffrey Bruma, who got 23 minutes under his belt and looked comfortable alongside John Terry.
The skipper had the final word in the game, his great goal line clearance to deny Olsson made it a great night all round for The Blues.
So its 9 goals unanswered since the disappointment and Villa Park, and given that at this stage last year cracks started to appear in our title hopes, The Blues are well positioned going into November.
The return of Cole, as well as solid performances from fringe players like Belletti and Ferreria can only strengthen the chance of the Premier League trophy being back at the Bridge come May.
Chelsea: Cech, Ivanovic, Carvalho (Bruma 67), Terry, Belletti (Ferreria 61), Essien, Lampard, J Cole (Sturridge 77), Ballack, Drogba, Anelka.
Subs not used: Hilario, Malouda, Deco, Kalou.
Blackburn: Robinson, Jacobsen (Salgado 60), Givet, Nelsen, Olsson, Emerton, Pedersen (Hoilett 69), Nzonzi, Andrews, Roberts (Kalinic 53), Diouf.
Subs not used: Brown, Jones, Reid, McCarthy.
Man of the Match: Joe Cole. At the top of the diamond, he sparkled. Great to see him back to his best.