Jose Mourinho suffered his first Premier League defeat since returning to Chelsea following a 1-0 loss against Everton at Goodison Park.
Mourinho's men were guilty of missing a host of chances and were made to pay for their wastefulness when Steven Naismith grabbed the winner on the stroke of half-time to hand Roberto Martinez his first Premier League victory as Everton manager.
Debutant Samuel Eto'o and Andre Schurrle were particularly guilty of missing good opportunities for Chelsea in the first half.
And Naismith pounced from Nikica Jelavic's header back across goal in first-half injury time.
Substitute Oscar felt he should have been awarded a penalty in the second half but referee Howard Webb waved away the protests.
Mourinho handed a first competitive start to transfer window signing Eto'o, with Fernando Torres dropping to the bench.
Everton gave a debut to Gareth Barry but fellow new boy James McCarthy had to settle for a place among the substitutes.
In a lively opening, Eto'o almost opened his Premier League account as early as the fourth minute.
Ramires found space on the right and his pin-point cross was met by the Cameroonian but he could only head over the bar from eight yards.
At the other end, Jelavic was equally as wasteful. Ross Barkley won possession in midfield and he supplied Naismith, whose excellent cross was met by the Croatian but he headed tamely at Petr Cech.
Tim Howard was given a huge reprieve in the 29th minute after a small lull in clear-cut openings.
Howard's attempted pass out of defence was intercepted by Eden Hazard. He centred to Eto'o, who looked destined to tap into the empty goal only to be denied by a wonderful sliding interception from Barry.
Chelsea continued to press and Mourinho was visibly frustrated as two good opportunities were not converted. First, Ramires flicked a ball in the air and volleyed at goal only to be denied by Howard.
The Brazilian then broke free again and prodded into the path of Schurrle, but the German blasted well over when one-on-one with the goalkeeper.
And Chelsea were made to pay for their profligacy in front of goal when Naismith notched the opener on the stroke of half-time.
Barkley crossed to Jelavic at the back post and he headed back across goal to the Scot, who could not miss when heading home on the goal line.
The second half started in similar fashion with Chelsea creating but unable to break down Everton's resistance.
Schurrle broke free but chipped over Howard into the side netting, before Howard parried a Hazard effort into the path of Eto'o but he failed to connect as the ball went harmlessly wide.
Oscar replaced Juan Mata, and the Brazilian thought he should have had a penalty in the 58th minute.
He ran across Sylvain Distin and was felled in the box but Webb was unmoved. Replays suggested Oscar may have had legitimate claims for a spot-kick as he appeared to touch the ball before the Frenchman.
With 20 minutes remaining, the lively Ramires stretched for a Branislav Ivanovic cross but he could only fire into the side netting.
Everton looked threatening on the counter attack as Chelsea searched for the equaliser and had a series of corners before Kevin Mirallas had an effort beaten away well by Cech.
The home fans thought their team had a late penalty when Seamus Coleman was brought down by Hazard, but the incident occurred just outside the box.
And they came desperately close to a second in the 88th minute when Leighton Baines saw his free-kick rebound off the crossbar.
|Coach: Roberto Martínez|
for N. Jelavić 66'
for S. Naismith 89'
for K. Mirallas 90+2'
|Opportunity knocks as Dyche plans for Barnes absence|
|Berbatov dreaming of Champions League semi-final|
|Benzema adds to Real´s injury concerns|
|Jenkinson: West Ham will not settle for mid-table|
|Montella calm over fan frustrations|
|Blanc: Barca are the model for PSG|
|Newcastle just need three more points - Janmaat|
|Gaya: Six finals left for Valencia|
|Muller wary of Porto counter-attacks|
|Bartomeu plays down Pogba link|
|Verratti hails ´essential´ Ibrahimovic|
|Zidane backs PSG to upset Barca|
|America v Montreal Impact: Klopas unfazed by host´s form|
|Vlaar open to Villa stay|
|Shepherd urges fans not to boycott Newcastle|
|Maritimo 1 Nacional 1: Tiquinho ensures derby finishes all square|
|Fiorentina 0 Verona 1: Diamanti and Neto pay the penalty|
|Elche 1 Real Sociedad 0: Bergara gifts win to hosts|
|Van Persie returns in Under-21 game|
|Turkish Super Lig Review: Galatasaray slip sees Fenerbahce go top|
|Russian Premier League Review: Arsenal Tula and Rostov maintain survival bids|
|Frontzeck named as Korkut´s replacement at Hannover|
|Lopetegui wary of Bayern backlash|
|Pastore plays down Cantona´s world best tag|
|PSG absences no excuse for failure - Blanc|
|Suarez sad to see Gerrard leaving Liverpool|
|Cleber injury adds to Hamburg woes|
|Northern Ireland free to play Romania at Windsor Park|
|Juve sweating on Vidal availability|
|Monaco v Juventus: Evra ready to take control|
|Striking concerns for Chelsea after Drogba injury|
|PSG and Chelsea have bid for Dybala, claims agent|
|Pogba can leave Juve for ´right offer´|
|Bendtner dropped after arriving late for training|
|Messi achievement unrepeatable, says Luis Enrique|
|Football League Preview: Preston and MK Dons battling to join Bristol City|
|Real Madrid v Atletico Madrid: Ancelotti optimistic amid injury concerns|
|Iniesta declared fit for PSG second leg|
|Bale remains a doubt for Atletico clash|
|Schweinsteiger set to face Porto, Ribery to miss out|
|No broken cheekbone for Silva|
|Final appearance can remove negativity at Villa - Fox|
|Bale selected in Football League Team of the Decade|
|PSV director: United and PSG want Depay|
|Korkut sacked by relegation-threatened Hannover|
|Sherwood: Pressure all on Arsenal|
|Newcastle in a ´dangerous moment´ - Colback|
|Kovac hopes to have Modric fit for Euro qualifier|
|Copa Libertadores Preview: Cruzeiro boss Oliveira does not fear sack|
|MLS Review: Revs extend unbeaten run, Timbers stun City|
|Fournier proud and disappointed|
|Shaw ready to make an impact|
|Hazard among best three in the world - Mourinho|
|Carver: Newcastle are in relegation battle|
|CAF Champions League Review: Setif get two away goals, Al Ahly denied late on|
|Inzaghi praises Milan derby officials|
|La Liga Review: Granada frustrate Sevilla, Villarreal´s woes continue|
|Inter should have had a penalty, Mancini fumes|
|Ligue 1 Review: Lyon return top after derby draw|
|Inter 0 Milan 0: Disappointing derby ends in stalemate|
|Primeira Liga Review: Sporting made to battle, Penafiel running out of time|
|Balotelli targets officials in latest social media outburst|
|Bundesliga Review: Werder Bremen edge Nordderby, De Bruyne rescues Wolfsburg|
|Serie A Review: Napoli close on stumbling Roma|
|Pochettino congratulates 30-goal Kane|
|Rodgers questions Liverpool´s mental strength|
|Carver counting on experience after latest defeat|
|Sherwood marvels at Grealish potential|
|Eredivisie Review: Dordrecht relegated as Go Ahead Eagles stun Feyenoord|
|Newcastle United 1 Tottenham 3: Losing streak continues amid fan boycott|
|Kouyate elbow on Silva accidental - Allardyce|
|Aston Villa 2 Liverpool 1: Delph ends Gerrard´s hopes of dream farewell|
|Pellegrini hails City response to derby defeat|
|Silva back home after Kouyate elbow|
|Manchester City 2 West Ham 0: Silva injury sours routine win|
|Bayern Munich v Porto: Neuer rallies Germans for uphill battle|
|Barcelona v Paris Saint-Germain: Marquinhos keeps the faith ahead of Camp Nou test|
|Fer closes in on QPR return|
|Crouch set for surgery|
|Dortmund confirm Tuchel as Klopp replacement|
|Adams leaves relegation-threatened Tranmere|
|Real still unsure over Modric injury|
|Tevez rubbishes Juve exit talk|
|Moyes: I had to fight to keep Rooney at United|
|Perth Glory 3 Melbourne City 1: Maclaren treble the difference|
|Dyche: Burnley are too honest|
|Illarramendi eager for Real stay|
|Hazard issues Chelsea warning|
|MLS Review: Injury-time winner buoys Galaxy, Martins shows class for Sounders|
|Pastore talents ´unpredictable´ - Blanc|
|Liverpool much bigger than City - Rodgers|
|AFC Champions League Preview: Evergrande look to progress|
|Clarke expects distraught Federici to bounce back|
|Toure is City´s scapegoat - agent|
|Allegri praises high-flying Juve|
|Athletic Bilbao 4 Getafe 0: Hosts end winless run|