Stoke came from behind to beat Chelsea 3-2 as Mark Hughes claimed a famous scalp over a disbelieving Jose Mourinho.
Goals from Peter Crouch, Steven Ireland and a late strike from Oussama Assaidi gave Stoke the win, despite a double from Andre Schurrle, who gave Chelsea the lead early on.
Chelsea drop to third in the table after Liverpool beat West Ham 4-1 at Anfield to go above on goal difference, while Stoke climb to 12th following their superb showing.
After the shock result, it will be interesting to see where Mourinho goes from here, with the Champions League clash against Steaua Bucharest with some level of importance.
Here are six things we took from the five-goal thriller.
Many believed that after the thrilling 4-3 victory over Sunderland at the Stadium of Light, Chelsea would operate more conservatively against Stoke.
But football is a funny game, and after Andre Schurrle's opener, the 'Chelsea of old' may have shut up shop and protected their lead.
Mourinho's style has changed, though, and the Blues know their defence is simply not good enough to sit on a one-goal lead.
He proved to be right as Peter Crouch equalised through another set-piece lapse from the away side.
The game turned into an end-to-end contest, with Stoke looking galvanised by drawing level, and Stephen Ireland's curled strike gave the Potters a shock lead.
Back came Chelsea, and their German forward Schurrle grabbed his second of the game which looked to have sealed a decent point at the Britannia Stadium.
Up popped Oussama Assaidi, on loan from Liverpool, with a stunning effort as the game approached stoppage time to seal a famous victory.
A worrying result for Chelsea, who suffer their third defeat away from home this season. Twenty-four goals in their eight away games suggests there is work to be done at the back, with 11 conceded.
Sometimes, a manager must appreciate that hard work can overcome flair in the world of football.
Jose Mourinho is one of those managers.
Because while his team selection was once again questionable, the inclusion of German winger Andre Schurrle was not. It appears Mourinho still doesn't know his best team, even after 15 games in charge. But Schurrle was an inspired selection on the right-hand side.
The 23-year-old Germany international signed from Bayer Leverkusen for £18 million in the summer and bagged a brace, adding to his solitary Premier League goal against Manchester City.
While perhaps less technically gifted than the likes of Juan Mata and Eden Hazard, Schurrle's gift lies in his tremendous level of efficiency on the wing. He will track back, work every channel possible and spark some life into his team.
Without him, the score could have been much worse today. Schurrle has certainly made his claim for a first-team spot, and after this performance, it would be difficult for Mourinho to deny him.
Aerial prowess, instinctive finishing and a general handful for defences, the question remains why Peter Crouch doesn't start more often for Stoke.
Of course, many will point to his tally of 78 Premier League appearances for the Potters—since joining the club in 2011—but there have been games whereby Kenwyne Jones, who has scored just four goals in his last 54 games, has started ahead of the former England striker.
Why? Your guess is as good as ours.
Two Premier League goals is hardly prolific, but thinking about Crouch as a target man, are there any better players to aim at in the air? Chelsea certainly struggled to deal with him, with Crouch scoring one and in all honesty, should have had more.
The 32-year-old is 6'7", and no striker is taller than that. No defender is taller than that.
Utilise Crouch on a regular basis, and Hughes will begin to reap the rewards.
Now up to 12th in the Premier League table, Stoke fans can relax...for now.
Nine points from their last six games has propelled the North East side out of the relegation zone and into mid-table, where a couple of good results might see them move into the top half.
Mark Hughes must be credited for their resurgence after a string of poor results, and the 3-2 victory over Chelsea is without question their best of the season.
In comparison to their 4-1 beating at the hands of the same opposition back in January under predecessor Tony Pulis, the supporters have to realise the change in attitude has helped turn around the club's fortunes.
Of course, a defeat against Hull and the critics will be back. But Hughes has done a sterling job in steadying the ship as the Welshman's side head into the festive period.
It's common knowledge that at 32 years of age, Ashley Cole is entering the final years of his glittering career. The performance, or lack of it, against Newcastle last month certainly highlighted that.
But this is one of the world's best left-backs over the past decade we're talking about here. Leaving him out is visibly hurting Chelsea.
Of course, Cesar Azpilicueta has performed admirably in that position in the past few games. Even in spite of this, he is not a left-back.
Deploying him there was a sign of boldness from Mourinho, showing he was not afraid to drop anyone.
Fine, point made.
But Azpilicueta struggled against Stoke and was identified as the weak link. Had Cole been up against Assaidi or Arnautovic, it may have been a different story altogether.
Cole needs to come in for the next game against Steaua Bucharest or even Crystal Palace three days after. The message is simple: return to the status quo, Jose, otherwise you may regret it.
Signed on loan from Aston Villa, supporters may have seen the signing of Stephen Ireland as merely a fringe player who can come in and provide some extra flair.
However, the 27-year-old has really shown his desire to resurrect his career, scoring three goals in 13 Premier League matches, highlighting his good relationship with Mark Hughes, whom he previously worked with at Manchester City.
The Ireland international scored a lovely curled effort against Petr Cech and was solid throughout the game as Stoke held on for three vital points.
There's never been any doubt about his ability; rather, his attitude has never been his strong point. That said, he showed fight and willingness to play for the Potters and got his reward.
Even amongst the creative maestros such as Eden Hazard and Juan Mata, Ireland showed himself to be the prime playmaker in Saturday afternoon.