Fernando Torres kick-started the win with his seventh goal in six appearances, while Frank Lampard marked his 500th Premier League start with a goal that made him the club's leading scorer in the top flight.
Ramires scored twice, with David Luiz, Branislav Ivanovic, Eden Hazard and Oscar also on target in a victory that emphatically drew a line under the club's recent slump.
There was much for Benitez to be pleased about, particularly the continuing good form of Torres.
But for Aston Villa, this result -- their heaviest top-flight defeat -- will come as a crushing blow after the improvement they have shown in recent weeks.
One of the first questions asked of Benitez when he took charge at Stamford Bridge was whether he could revive Torres.
The interim manager insisted he could and the striker's recent strike rate suggests Benitez has been good to his word, as the sharpness of Torres's third-minute header demonstrated.
Picked out by Cesar Azpilicueta's cross from deep, the Spain international connected with a powerful header, twisting his body to direct the ball beyond Brad Guzan from 16 yards out.
It was the perfect start for the Blues, who came into the game on the back of an impressive 5-1 League Cup quarter-final victory at Leeds United.
Villa are also in the last four of that competition and Paul Lambert's side arrived in west London unbeaten in their previous six games.
But any confidence they have built up during that impressive run was shredded during a first half when Chelsea easily assumed complete control of the game.
Chelsea thought they should have been given the chance to double their lead in the 22nd minute when Torres appeared to be held by Nathan Baker, but referee Phil Dowd waved away appeals for a penalty.
They soon had their second, however, when Luiz assumed responsibility for a free-kick 25 yards out, curling the ball up, over the wall and inside Guzan's right-hand post in the 29th minute.
Lambert had understandably kept faith with the side that won 3-1 at Liverpool last weekend and it was, with an average age of just under 24, the youngest team Villa had ever fielded in the Premier League.
Their inexperience showed as they collapsed under the weight of the Chelsea pressure, falling further behind when Ivanovic made it three in the 34th minute.
A Chelsea corner was met by Gary Cahill, whose deflected shot was beaten away by Guzan, but only into the path of Ivanovic, who headed home unchallenged.
Villa's priority was to save themselves from humiliation in the second period, but it quickly became clear that that task would prove beyond them.
Juan Mata produced an outstanding save from Guzan five minutes after the restart, before Torres had a header ruled out for offside.
It was left to Lampard to add the fourth, the Blues' stand-in skipper marking his big day in style with a powerful low drive from 25 yards.
Chelsea scored their fifth in the 75th minute when Ramires collected a pass from fellow substitute Lucas Piazon and stroked the ball through Guzan's legs.
Four minutes later, Chris Herd fouled Oscar and the Brazilian picked himself off the floor to convert the penalty.
Hazard then exchanged passes with Piazon before creating space inside the area and beating Guzan with a vicious rising drive in the 83rd minute.
Guzan saved excellently from Piazon's penalty after the Brazilian had been fouled by Ciaran Clark, but that was only a temporary reprieve before Ramires struck Chelsea's eighth.