By Dan Harrison
Villa experienced the full range of emotions to earn a sensational draw at Stamford Bridge.
Gerard Houllier's team picked themselves up from the frustration of falling behind to Frank Lampard's penalty to overturn Chelsea's lead, only for the double winners to strike a double blow in the final six minutes through Didier Drogba and John Terry.
But the reward for a courageous performance came in the form of a dramatic last-minute equaliser from Ciaran Clark, who excelled in an unfamiliar left-back role.
He came in as part of a rejigged back four, which saw Richard Dunne return to partner James Collins in the centre while Carlos Cuellar moved to the right.
Despite shipping three goals, the quartet provided the backbone to a much-improved Villa display following back-to-back defeats against Tottenham Hotspur and Manchester City.
However, it seemed as though there would be no change in Villa's luck when referee Lee Mason awarded a dubious penalty which allowed Lampard to fire Chelsea into a 23rd minute lead.
Everyone of claret and blue persuasion was up in arms when the official pointed to the spot after James Collins' aerial challenge on Florent Malouda, which resulted in the Chelsea forward going to ground.
It came as a hammer blow after an encouraging start from the away side, with Gabby Agbonlahor shooting wide from the edge of the area and Ashley Young almost catching Petr Cech out with a cross-cum-shot.
Villa were presented with a severe test of character - though it was a challenge they more than stood up to.
Mason levelled the penalty count on 41 minutes, allowing Young to thump home an equaliser which lifted the travelling supporters.
And the claret and blues began the second-half at an exhilarating tempo, with Cech getting down low to hold a powerful James Collins header.
Within two minutes of the restart Villa were ahead. Emile Heskey once again demonstrated how crucial his presence up front can be by leaping at the back post to connect with Downing's sublime cutback.
A mammoth task still lay ahead for the away team against the reigning Barclays Premier League champions and goalkeeper Brad Friedel had to be at his best to ensure Villa's lead remained intact until the closing stages.
Firstly, the American's strong hands pushed a thumping Lampard volley over the bar and Friedel then stood tall to thwart Malouda from a tight angle.
But while Villa showed unquestionable spirit throughout this enthralling contest, Chelsea displayed the resolve of champions to turn the tables on their opponents.
On 84 minutes, Drogba was in the right place at the right time to slot home an equaliser following a goal-mouth scramble and, with less than a minute of normal time to play, captain John Terry tucked away the rebound after Friedel acrobatically pushed away Drogba's header.
Cue the rescue act from Clark, who had been exemplary in a defensive capacity before becoming the hero at the sharp end.
The 21-year-old ghosted into the penalty area to beat the offside trap and guide substitute Marc Albrighton's floated left-wing cross past Cech.
Villa's players sprinted to the corner to join their supporters in celebration.
Who could blame them? It was the least they deserved following a passionate response to the two defeats suffered over the festive period.
CHELSEA: Cech; Ferreira, Bruma, Terry, Cole; Ramires, Essien, Lampard; Anelka, Drogba, Malouda. Subs: Turnbull, Bosingwa (for Ferreira, 57), Kalou (for Ramires, 73), Sturridge (for Anelka, 78), Van Aanholt, McEachran, Mellis.
VILLA: Friedel; Cuellar, Collins, Dunne, Clark; Downing, Petrov, Reo-Coker, A Young; Agbonlahor, Heskey. Subs: Marshall, Pires, Albrighton (for Agbonlahor 84), Delfouneso, Bannan, Lichaj, Herd.