Chelsea captain John Terry scored a 99th-minute equaliser as the Blues came from behind on three separate occasions to draw 3-3 with Everton in Saturday's explosive Premier League encounter at Stamford Bridge.
Everton looked on course to complete the league double over Chelsea for the first time since the since the 1978-79 season, but Terry levelled in the ninth minute of additional time to help his team avoid defeat.
It was Everton that started the brighter at the Bridge, with Ross Barkley having a shot blocked in the fifth minute during a period where the visitors were dominating possession of the ball. The rebound almost fell to Romelu Lukaku on his return to Chelsea, but Thibaut Courtois was on hand to claim.
Chelsea's first real chance came in the 16th minute when Willian found space inside the Everton box, but his low strike was kept out by the diving Tim Howard. Moments later, Kevin Mirallas had the ball in the back of the net down the other end, but the Belgian was correctly called offside.
The game started to open up around the 20-minute mark and Everton once again came close through Bryan Oviedo, but the Costa Rican could only place a first-time volley wide of the post.
Lukaku against Kurt Zouma was a battle that continued to develop as the match approached the 30-minute mark, and it was the Chelsea defender that managed to get the best of the Belgian on a couple of occasions.
Mirallas was next to come close for Everton late in the first period, but his low strike was tipped wide of the post by Courtois as the two teams, who managed just one shot on target apiece in the opening 45 minutes, entered the interval on terms.
Everton took the lead early in the second period, however, when Leighton Baines's low cross from the left was turned into his own net by Terry, who could not sort his feet out.
The visitors should have been 2-0 ahead just three minutes later when Mirallas fed Barkley inside the Chelsea box after more sloppy play from the Blues, but the England midfielder rattled the near post.
Roberto Martinez's side did have their second in the 56th minute, however, when Baines found Mirallas, who turned outside the box before firing an effort into the bottom corner.
A clever flick from Cesc Fabregas almost halved the deficit in the 62nd minute, but Howard was on hand to make a fine save during an extended spell of pressure from the wounded hosts.
A breathless second half continued to produce and Chelsea were back in the game in the 64th minute when Costa took advantage of a mix-up between Phil Jagielka and Howard before rolling home from close range.
Just two minutes later, it was all square as Costa set up Fabregas and the Spanish international's low strike was deflected into the back of the net for 2-2.
Everton had a wonderful chance to regain the lead in the 76th minute when Mirallas went through one on one with Courtois, but the Belgian fired straight at his fellow countryman as Chelsea survived a dangerous counter.
John Obi Mikel then came close for Chelsea with a long-range strike, but the midfielder's effort was wide of the post as Everton resisted the late pressure.
That was not the end of the drama, however, with Everton taking a 3-2 lead in the 90th minute when Ramiro Funes Mori turned home at the far post following a corner.
Seven minutes were added at Stamford Bridge due to a host of injuries and the story was not finished as Terry, who looked offside, bundled home with just about the final kick as Chelsea secured a share of the spoils.
The result has left Chelsea in 14th position in the table, while Everton, who have missed the chance to rise three places, remain 11th.
