Chelsea cruised to the top of the Premier League with an emphatic victory over Everton at Stamford Bridge thanks to two goals from Eden Hazard with Marcos Alonso, Diego Costa and Pedro also on target.
Not since winning the 2014-15 title have Chelsea led the top flight, but they took advantage of Manchester City's 1-1 draw with Middlesbrough earlier on Saturday to do so, though Arsenal or Liverpool could displace them by winning their respective matches on Sunday.
Antonio Conte's team, unchanged for the fourth straight league match, ran riot and punished visiting manager Ronald Koeman for his decision to switch to a three-man defence.
That surprise tactical change came despite Everton having ended a run of five games in all competitions without a win at home to West Ham last time out.
Hazard opened the scoring in the 18th minute, converting for the fourth successive league game for the first time in his career, before Marcos Alonso opened his Chelsea account with his maiden goal for the club just 70 seconds later.
Koeman sent Kevin Mirallas on for Bryan Oviedo in a bid to add stability through a more familiar formation, but the hosts continued to dominate and Diego Costa fired home three minutes before the interval.
Hazard struck a sensational second 11 minutes into the second half before Pedro added a goal to his two assists, rounding off a phenomenal display of attacking football that extends Chelsea's unbeaten run at home against Everton to 22 matches.
There were fireworks at Stamford Bridge ahead of kick-off and sparks soon flew on the pitch when Seamus Coleman's lunge on Costa went unpunished by referee Robert Madley.
Chelsea applied all the early pressure and made the breakthrough when Hazard stepped inside from the left and curled an excellent finish past Maarten Stekelenburg, returning from a foot injury in place of Joel Robles.
Within two minutes Conte's team doubled their advantage, Alonso scoring through a gap in Stekelenburg's legs after arriving to meet Pedro's square pass from the right-hand side of the box.
Victor Moses volleyed against the post in the 34th minute and Koeman responded by replacing Oviedo with Mirallas and reverting to a four-man defence.
That did not stop the flood of goals, though, as Hazard's corner was flicked on by Nemanja Matic at the near post and Costa drilled home a half-volley, though he failed to add to his tally from a one-on-one in first-half stoppage time.
Chelsea continued to dominate and brilliant interplay between Hazard and Pedro on the right saw the Spaniard beat Ashley Williams and fire a low effort inside the near post.
Stekelenburg kept out an acrobatic volley from Costa but the striker was integral to the hosts' fifth in the 65th minute. After nutmegging Phil Jagielka he teed up Hazard, and the winger's shot rebounded straight to Pedro for a simple finish.
Pedro and Hazard received standing ovations as they were replaced in the closing stages, while Stekelenburg produced a good save to tip a volley from David Luiz over.
Everton failed to get a single shot on target throughout the 90 minutes, with Chelsea, for whom fit-again John Terry made his first top-flight appearance since September 11 as a late substitute, keeping a clean sheet for the fifth straight Premier League match.