The visitors were dominated from start to finish by a Toffees side which has been rejuvenated by its work in the January transfer window
The Toffees opened the scoring just five minutes in thanks to the returning Steven Pienaar's wonderfully controlled strike.
They then pinned Chelsea back with some brilliantly incisive attacking and got a deserved second through Denis Stracqualursi to follow up their win over Manchester City with another impressive victory.
Given that Everton had beaten the league leaders at Goodison Park in its last home game, it was unsurprising the Toffees started full of confidence and somewhat caught Chelsea on its heels. The visitors looked shaky defensively and paid the biggest price just five minutes in as Everton took the lead.
A coming together between Tim Cahill and Lampard saw the ball loop over the Blues’ defense and somewhat fortuitously into the path of Pienaar who controlled brilliantly on his chest and smashed beyond Petr Cech.
Despite the early nature of the goal, it was no more than the hosts deserved and they almost added to it just moments later as a Neville cross was met by the head of Stracqualursi, who nodded inches wide of the post.
A Donovan drive from distance, which stung the palms of Cech, gave the hosts further hope of gaining a Premier League scalp, as Andre Villas-Boas’ men appeared rattled.
It took 25 minutes for the Londoners to show any sort of fight but a chance for a Fernando Torres head at goal was brilliantly denied by Sylvain Distin before Daniel Sturridge saw his shot desperately blocked at the edge of the box.
A wild kick from a frustrated Raul Meireles on the breaking Stracqualursi conveyed Chelsea’s frustrations in the first half but the hosts failed to capitalize by wasting the free-kick, taking it short.
The pace did not appear to have slowed as the second half commenced, with both sides continuing to show the attacking intent which made the game easy to watch for neutrals.
Stracqualursi’s twist and turn in the box ended in a blocked shot but emphasized Chelsea’s position as the side under the cosh from an Everton whose creativity has improved no end since a productive January.
Another weak Torres header from a deep cross served to underline Chelsea’s lack of attacking thrust and there appeared no way back into the game with Everton counter-punching brilliantly.
And it was to prove so as the Toffees landed the knockout blow with 15 minutes remaining on the clock. A brilliant run in off the right from Donovan found the Blues’ defense backpedalling, and the American’s wonderfully weighted pass allowed striker Stracqualursi to smash beyond Cech, despite the keeper getting a palm to the ball.
Chelsea's game was up with that goal and Villas-Boas appeared to know it, removing Mata - one of the few impressive performers - for youngster Romelu Lukaku.
Everton was then little troubled by their visitors, as it had in truth been throughout the match, and kept the ball patiently in order to see out a deserved win which may mark yet another late-season renaissance.