Stoke - Problems mounted for Chelsea manager Jose Mourinho as the flatlining Premier League champions crashed to a 1-0 defeat at Stoke City in his absence due to a stadium ban on Saturday.
Marko Arnautovic struck early in the second half to inflict a third consecutive league defeat on the London club for the first time in 16 years and for the first time since Roman Abramovich took control at Stamford Bridge in 2003.
The defeat also means that for the first time in his illustrious managerial career, Mourinho has now lost seven league games in a single season, with the campaign still less than one-third complete.
Mourinho was banned from setting foot in any part of the stadium complex by the Football Association after berating referee Jon Moss at half-time of his side's recent defeat at West Ham United.
With the Portuguese reportedly watching from the team hotel, managerial duties were carried out by Chelsea's assistant first-team coaches Steve Holland, Silvino Louro and Rui Faria, and they saw Stoke open the scoring after 53 minutes of an absorbing game.
Xherdan Shaqiri played Glen Johnson in down the right wing and although his cross could not be converted by Jon Walters, Arnautovic made no mistake with an acrobatic back-post volley from eight yards.
The game had caught fire in the opening minute, when Arnautovic dispossessed Cesar Azpilicueta and allowed Charlie Adam to cross for Shaqiri to volley spectacularly over the Chelsea crossbar.
While Chelsea supporters repeatedly chanted the name of their absent manager, the home support were more intent on venting their anger at visiting forward Diego Costa, whose physical, often petty, battle with Ryan Shawcross was one of the contest's main talking points.
There were also outbreaks of fine football from both sides, such as Chelsea's 14th minute counter-attack, started by Baba Rahman and continued by Eden Hazard, which ended with Ramires poking wide from Willian's pass.
Former Stoke goalkeeper Asmir Begovic saved well, at full stretch, from Johnson as the hosts responded, but the visitors began to take control, with Jack Butland tipping Ramires's 25-yard volley over the bar.
Pedro Rodriguez's superb long pass then freed Hazard down the left and his cross was narrowly missed by Costa as he sprinted in for what would have been a magnificent goal.
Not that Stoke did not present a threat themselves, especially in the form of skilful right winger Shaqiri, who showed superb trickery to beat Rahman and cross for Walters to head onto the roof of the net.
Still, it required more solid keeping from Butland to thrust out a leg and deny Costa late in the half after a Pedro back-heel opened up a shooting opportunity for the Chelsea forward.
A goal behind, and with the game becoming ever more fractious, Chelsea sought a way back into contention, with Hazard showing clever footwork on the edge of the Stoke area before shooting over.
But Stoke, with just one previous home league win behind them this season, drew confidence from taking the lead and saw Johnson shoot off-target before Arnautovic headed just over.
When Willian's pass then found Pedro for a curling left-foot shot that beat the dive of goalkeeper Butland, only to hit the post and bounce to safety, it appeared that luck was against Mourinho's side.
After 80 minutes, and two back-heels in the build-up, substitute Cesc Fabregas set up Hazard for a shot, but again, fortune was against Chelsea as the ball deflected behind for a corner.
Walters then wasted a good chance to put the game out of reach, blazing over from Mame Biram Diouf's pass.
Chelsea substitute Loic Remy still had time to chase Oscar's through-ball and hurdle Butland before losing his footing when either a penalty, or a shot into an open net, might have been the outcome.