The champions beat Blues to become Manchester United's closest challengers, moving to within six points of the leaders and giving themselves a glimmer of hope of retaining their crown.
Once again looking far more comfortable in their tried-and-trusted 4-3-3 formation, Malouda and Kalou scored brilliant first-half goals, and the former struck again before Sebastian Larsson netted a consolation from the penalty spot.
Chelsea therefore capitalised on United's failure to win at Newcastle yesterday and, with a trip to Old Trafford to come, there is a slim chance they could yet snatch the title.
Realistically, though, they would need to win all their remaining games and, on the evidence of tonight, their best chance of doing so would be sticking with Drogba, Malouda and Kalou up front.
The failure of Torres - who came off the bench to extend his goal drought to 893 minutes - to earn a recall was significant as it was the first time he had not started after being on the bench in the previous match.
Ancelotti, who last week appeared all but resigned to losing his job, had clearly decided the disparity between his form and Drogba's was too severe to ignore.
With square pegs in square holes, it took Chelsea's front three less than three minutes to unlock Blues with a super goal.
John Terry sprayed the ball wide to the recalled Paulo Ferreira, whose cross was flicked on by Drogba for Malouda to crash home.
Blues goalkeeper Ben Foster, who had proven unbeatable in the reverse fixture at St Andrew's, almost fumbled Drogba's 25-yarder into his own net and was nearly chipped by the resurgent Ivory Coast striker.
Kalou was also not afraid to try his luck and produced a magnificent second goal in the 26th minute, turning away from Roger Johnson, side-stepping Stuart Parnaby and unleashing an unstoppable 20-yard shot into the corner of Foster's net.
Players were taking regular drinks breaks on what was a sweltering evening at Stamford Bridge.
But it was the visitors' defence which was feeling the heat as Drogba's snapshot forced Foster into a fingertip save, Kalou nodded over the bar, Foster saved Lampard's tame effort and Michael Essien hooked wide.
Blues' first-half chances fell to Cameron Jerome, whose Premier League goal drought stretches back to November.
The striker saw one effort tipped wide by Petr Cech and also saw a shot on the turn blocked after being set up by Alexander Hleb, who was handed his first start for two months despite saying this week he did not want to stay at the club when his loan expires.
Parnaby earned what proved the game's only booking for bringing down Kalou shortly after the restart, with Essien seeing his header from Drogba's resulting free-kick deflected behind.
Chelsea began to get sloppy and Johnson headed a corner just wide before Cole was replaced by Ryan Bertrand, the 21-year-old finally earning his debut after a career spent out on loan.
The newcomer took less than six minutes to make an impact, Malouda rising to head home his 62nd-minute cross unchallenged.
Torres had been warming up in the meantime and, with the game won, he and Nicolas Anelka made their entrance in the 67th minute, replacing Malouda and Kalou.
The remainder of the game became about whether Torres could end his 870-minute goal drought for club and country, 701 of them in a Chelsea shirt.
"He's gonna score in a minute", the Chelsea fans sang about their £50million man.
But it was Blues who got the next goal thanks to the latest in what is becoming an alarming collection of rash challenges from David Luiz.
The Brazilian clearly tripped substitute Matt Derbyshire and, after snatching the ball from team-mate Craig Gardner, Larsson stepped up to score.
Derbyshire also dragged wide after Anelka lost the ball in midfield.
With five minutes remaining, Larsson was penalised for a backpass but Drogba refused to give Torres the chance to break his duck, duly blazing the indirect free-kick over the bar.
