Fernando Torres scored his first hat-trick for Chelsea as they celebrated reaching the Champions League final by roaring back into contention to qualify for next season's competition via their league position.
Torres and the Blues produced the polar opposite of a European hangover after Tuesday's astonishing semi-final triumph over Barcelona by burying QPR in a Stamford Bridge mudbath.
Their biggest ever win over QPR avenged October's incendiary west London derby defeat at Loftus Road, the visitors' goal difference taking a pounding as they stayed just outside the relegation zone having played a game more than third-bottom Bolton.
They will need to defend infinitely better than this to stand a chance of survival, conceding to Daniel Sturridge after just 48 seconds and allowing John Terry to make it 2-0 before Torres' treble, a goal from substitute Florent Malouda and a late consolation from Djibril Cisse.
Terry had the last laugh at the end of a week in which his sending off somehow failed to cost Chelsea at the Nou Camp and his upcoming racism trial took centre-stage again when pre-match handshakes were cancelled.
Both he and QPR defender Anton Ferdinand - the man he denies racially abusing - were mercilessly targeted by opposition fans, as they had been in January's FA Cup tie at Loftus Road.
Chelsea owner Roman Abramovich, who on Saturday bankrolled the club's first summer signing in Marko Marin, was at Stamford Bridge to watch Roberto Di Matteo's latest attempt to convince the Russian to give him the manager's job full-time.
It took the home side - who had been in danger of going a whole Premier League season without winning a London derby for the first time - barely a quarter of the game to make another case for the Italian.
With several players playing for a place in the FA Cup and Champions League finals, they tore into Rangers from the first whistle and Sturridge's screamer hit the net inside a minute.
Ferdinand provided an unwitting assist as Sturridge played the ball back off the defender before unleashing an unstoppable curler on his weaker right foot, although Paddy Kenny might claim he was unsighted by an offside Frank Lampard.
QPR tried to hit back but Chelsea might have had a penalty when makeshift centre-back Jose Bosingwa's drive hit the hand of Clint Hill, who was badly exposed as Terry made it 2-0 in the 14th minute.
Kenny tipped over a delightful Lampard chip but it was in vain as Terry got in front of Hill far too easily to nod home Juan Mata's corner.
The celebrations were sensibly muted from Terry but the home fans could not have been more delighted.
They were on their feet again five minutes later in appreciation of a brilliant Torres goal, the striker starting and finishing a blistering move by rounding Kenny after a superb ball from Salomon Kalou.
QPR were reeling but the fourth goal was unforgivable, a horrible mix-up between Nedum Onuoha and Kenny gifting Torres a left-foot finish he was in no mood to pass up.
Another fine move almost saw Lampard make it 5-0 and Torres complete his hat-trick as the driving rain was briefly replaced by glorious sunshine.
It was still wet enough for Michael Essien to be given the benefit of the doubt when he dived in on Cisse and Joey Barton was even more fortunate when he raked his studs down the ankle of Mata, who required treatment.
Mata would have made it 5-0 shortly after half-time but for a powder-puff finish, while Petr Cech was finally called into meaningful action when he somehow clawed Jamie Mackie's drive out of the top corner.
Barton was finally booked and Kenny delayed Torres' hat-trick with a good save but the £50million man made no mistake to complete his first treble since September 2009, beating the offside trap to clip Mata's pass into the far corner.
Abramovich high-fived his companions in the directors' box and he was celebrating again 10 minutes from time when substitutes Ramires and Malouda combined thanks to a Ferdinand blunder.
There was still time for Sam Hutchinson to make his first appearance since coming out of retirement and Cisse to drill home a consolation, but the damage was already done.
Chelsea Cech, Ferreira, Bosingwa (Hutchinson 81), Terry, Cole, Mata (Malouda 67), Essien, Lampard, Sturridge, Torres, Kalou (Ramires 73).
Subs Not Used: Turnbull, Romeu, Drogba, Meireles.
Goals: Sturridge 1, Terry 13, Torres 19, 25, 64, Malouda 80.
QPR Kenny, Onuoha, Ferdinand, Hill, Taiwo, Mackie, Barton, Derry, Buzsaky (Traore 66), Cisse, Zamora (Wright-Phillips 78).
Subs Not Used: Cerny, Gabbidon, Campbell, Young, Smith.
Goals: Cisse 84.
Att: 41, 675
Ref: Howard Webb (S Yorkshire).