Chelsea's weakness in defence was exposed emphatically as a hat-trick from Wolverhampton Wanderers' Matheus Cunha saw the visitors come from behind to grab a 4-2 win at Stamford Bridge on Sunday.
Chelsea needed a strong reply after losing 4-1 at Liverpool midweek. They did so, briefly, on Sunday.
The sides exchanged half-chances during the opening 15 minutes, Cunha and Pedro Neto drawing decent saves from Djordje Petrovic in Chelsea's goal, while at the other end Cole Palmer saw a left-footed shot deflect wide from outside the box and Christopher Nkunku was blocked by Jose Sa as he ran through on goal.
Then, Chelsea when went ahead in the 20th minute. The game needed a spark of inspiration, and it came from Moises Caicedo. Chelsea's record signing collected the ball centrally midway inside the Wolves half and with precision found the run of Cole Palmer. Caicedo's pass did the hard part for him, and Chelsea's top scorer placed it first-time into the corner with a cool flick of the boot.
But Chelsea's lead lasted just three minutes, with Cunha's shot taking a hefty deflection off Thiago Silva to leave Blues keeper Petrovic wrong-footed as it whistled into the net.
Mauricio Pochettino could barely watch in the 43rd minute when Rayan Ait Nouri's shot deflected in for an own goal off Chelsea defender Axel Disasi.
The atmosphere at Stamford Bridge became even more tense in the 63rd minute as Neto teed up Cunha to drive in Wolves' third goal.
Cunha's 82nd minute penalty, awarded when he was fouled by Malo Gusto, capped a miserable afternoon for Pochettino.
Chelsea did pull things back a bit with Silva's close-range finish in the 86th minute, but the game was done and dusted by that time.
Chelsea supporters near the dugout were angry with their team's slow pace and a perceived lack of fight, making their feelings known at half-time in a furious chorus of boos. But things only got worse after that, and could remain so for some time.
It has been an uninspiring first season in charge for Pochettino and the former Tottenham boss is certain to face questions about his future unless results improve quickly.
Chelsea co-owner Todd Boehly has already shown his ruthless side by sacking Graham Potter after less than seven months in charge last term.
Pochettino's side were booed off by home fans at the end of a second loss in four days, while the name of former owner Roman Abramovich could be heard ringing around the ground.
Chelsea, who were quiet in the January transfer market after spending more than $1 billion in three previous windows, dropped to 11th place and below Wolves in another below-par league campaign under the club's American ownership.
After the win, Wolves manager Gary O'Neil was understandably ecstatic.
"Tough place to come, Chelsea have an extremely talented squad. [It was] just a real belief in our group," he told BBC Sport.
"We tidied up bits that worked well against Manchester United and looked much better. It was a real good team performance and an enjoyable one for us, I can't lie.
"I didn't really like us at 4-1, a little lack of focus. It's a talented group. I really enjoyed it and the lads deserve massive credit. We have come back from setbacks a lot. We suffered heartbreak three days ago after working our socks off to get back against Manchester United. But it was straight to business."
Meanwhile, a brilliant strike from Callum Hudson-Odoi earned struggling Nottingham Forest a welcome point in a 1-1 draw at Bournemouth.
Former Chelsea forward Hudson-Odoi scored with a curling shot from outside the box following a well-drilled Forest free-kick routine in first-half stoppage time to draw his side level.
Bournemouth took the lead from a Lloyd Kelly corner in the fifth minute, with Justin Kluivert firing the hosts in front from point-blank range after latching on to Luis Sinisterra's knock on.
