Chelsea were held to a 1-1 draw by Burnley as Robbie Brady's stunning free kick cancelled out Pedro's early opener at Turf Moor.
Antonio Conte's side still have a 10-point lead at the top of the table and their fixture list is relatively kind, but what can their upcoming opponents learn from Sean Dyche's side about how to stop them?
From keeping cool under pressure to upping the off-the-ball intensity, we pick out the lessons from Burnley's performance on Nissan Super Sunday…
Keep cool
Of the 19 Premier League games in which Chelsea have scored first this season, they have gone on to win 16 of them. Conte's men have a habit of grinding their opponents down after netting the opening goal, but Burnley's response to Pedro's strike was a key factor in the turnaround.
Rather than allowing Chelsea to run away with it, Burnley kept their heads up and rallied. "It rattled Burnley and it was bound to, but to their credit their reorganised, settled themselves and got back into the shape they planned at the start," said Sky Sports pundit Alan Smith.
Burnley ensured Pedro's seventh-minute opener was Chelsea's last shot on target of the afternoon, and they had chances to win it themselves, with Matt Lowton spurning one gilt-edged opportunity after Brady's leveller. In his post-match interview with Sky Sports, a delighted Dyche praised his side's strong mentality.
"I was super impressed with the reaction to their goal," he said. "With them scoring so early, there was no disappointment, we stayed on the front foot and I was really pleased with that. There is growth in the side. They are maturing as individuals and as a side, with the assuredness that it takes to play in the Premier League."
Don't try to match the formation
Some of Chelsea's recent opponents have opted to mirror their 3-4-3 formation. The tactic worked for Tottenham in their 2-0 win at White Hart Lane last month, but most teams are not equipped to go toe to toe with the Blues. Burnley chose to line up in their usual 4-4-2 formation instead. It showed the value in sticking to what you know.
"We wanted to be brave," Dyche told Sky Sports afterwards. "If you change the shape for their shape, there's a good chance they will be better at it than you. So we wanted to stick with what we do. We wanted to mix the game up and make it uncomfortable. After the first 20 minutes or so, I thought we did."
The presence of two strikers in Andre Gray and Ashley Barnes ensured Burnley carried a constant threat on the counter-attack. But as well as having the bodies to cause Chelsea problems, the set-up allowed them to defend in numbers too. Gray and Barnes screened from the front, and wide players George Boyd and Brady tracked back diligently on the flanks.
"You've got to give full credit to Sean Dyche's tactics," said Wales boss Chris Coleman in the Sky Sports studio. "Yes it was set up as 4-4-2, but as soon as Chelsea ventured into the Burnley half, Boyd and Brady tracked the wing-backs and it turned into a six. If that was another manager managing Burnley, we'd all be saying that's amazing."
Contain the counter-attack
Arsenal showed the dangers of allowing Chelsea to play on the counter-attack last weekend, and the Blues' opener at Turf Moor was another reminder of the speed at which they can break forward. After those early moments, however, Burnley managed to nullify the league leaders' major weapon.
They were happy to allow Chelsea a 71 per cent share of the possession - their highest of the entire season so far - but with the defence sitting deep, there were precious few opportunities for Conte's men to get in behind. Ceding possession can be a dangerous game, but if you get the defensive shape right, Burnley showed it's an effective way of keeping Chelsea at bay.
Win the midfield battle
One of the risks of allowing Chelsea to dominate possession is that N'Golo Kante and Nemanja Matic will dictate play from central midfield, but Burnley managed to limit their influence. In the Sky Sports studio, Coleman highlighted the role of Joey Barton and Ashley Westwood in keeping them quiet.
"In the first 15 minutes Burnley were going backwards a lot, but once Chelsea scored I'm quite sure Sean Dyche told Barton and Westwood to press Matic and Kante and not worry so much about Hazard and Pedro because they were sitting deep and inviting them on," he said. "When they pressed higher and won it earlier, it gave Chelsea something else to think about."
Barton led the way, ranking top for tackles (five) and ball recoveries (11), and it paid off when he provoked the foul from Matic for the equaliser. Ashley Barnes dropped back to share pressing duties, with Burnley leaving Chelsea to pass the ball harmlessly between their defenders. Indeed, it was telling that Cesar Azpilicueta and David Luiz had the most touches.
When Burnley did have the ball, they bypassed Chelsea's midfield with a typically direct approach. The stats showed they played 92 long balls in total, giving Andre Gray plenty of opportunities to stretch Chelsea's backline and ensuring the game was played on their own terms. "With the long ball and the second balls, it's not easy to play here with Burnley," conceded Conte afterwards.
Increase the intensity
Having a plan to stop Chelsea is one thing, but carrying it out requires huge amounts of effort. Burnley were not found wanting in that regard. Premier League tracking data showed they covered over six kilometres more than Chelsea. Their collective total of 121km was more than the Blues have managed in any game all season.
Boyd typified Burnley's approach, ranking top for both distance covered and high-intensity sprints, while Westwood, Barton and Barnes weren't far behind. Their monumental efforts highlighted the emphasis placed on the midfield battle, and their stamina allowed Burnley to stick to the plan right up until the final whistle.
"What was happening in the middle of the pitch was not for the faint-hearted," said Alan Smith. "There was no room for passengers there. There were some crashing challenges, it was old-school stuff. Huge admiration for Sean Dyche and for his players, who had to put the effort in to carry out those orders."
If Swansea, Watford, West Ham and Stoke are to stop Chelsea in the next four weeks, they will need to show similar levels of industry. Burnley have shown exactly what it takes.