Roberto Martinez recorded his first Premier League win since his appointment as Everton manager with victory over Chelsea at Goodison Park.
Steven Naismith's header in first-half injury time inflicted Jose Mourinho's first domestic defeat since returning to Chelsea - but this was a win of huge significance for Martinez.
Chelsea's best chances came in the first half but were wasted by Eto'o and Andre Schurrle. After the break they were resisted by an outstanding defensive performance by Everton, who maintained their concentration and strength to the final whistle while also threatening.
Mourinho looked increasingly agitated and frustrated as the clock ticked down - and when referee Howard Webb sounded the final whistle, Goodison Park rocked to a thunderous standing ovation for Martinez's team.
Eto'o was given an instant debut and should have marked it with an early goal when he showed clever movement to pull away onto Ramires' cross, only to direct it back across Howard and wide.
Just as Everton looked as though they were going to be grateful to reach half-time level, they landed a classic counter punch in stoppage time when Jelavic did well to head Leon Osman's cross in the direction of Naismith, who headed in from virtually on the line.
Chelsea moved up a gear immediately after the break but Schurrle was once again off target when he could only hit the side-netting as he attempted to lift his finish over Howard.
Mourinho made a double change after 56 minutes, sending on Oscar and Frank Lampard for Schurrle and Juan Mata.
As Everton pushed for a second, David Luiz was perhaps fortunate to escape with only a yellow card when he pulled back Mirallas but the sheer distance he would have had to cover did not make it a clear goalscoring opportunity.
Ross Barkley's inexperience showed on occasion but the outstanding young player showed relentless drive and, after he was again fouled, Leighton Baines clipped a free-kick on to the bar.