Manchester City shook off the impact of a COVID outbreak in their ranks to outclass Chelsea 3-1 at Stamford Bridge and put themselves firmly in the Premier League title mix on Sunday.
City manager Pep Guardiola had six players unavailable after positive tests but his team responded in scintillating fashion with goals by Ilkay Gundogan, Phil Foden and Kevin De Bruyne dismantling Chelsea in 16 first-half minutes.
After that it felt like damage limitation for a subdued Chelsea side whose season is unravelling alarmingly after a strong start, although substitute Callum Hudson-Odoi did grab a stoppage-time consolation goal.
City's vintage display lifted them to fifth in the table with 29 points, four behind joint leaders Liverpool and Manchester United having played one game less.
A fourth defeat in six league games leaves Chelsea in eighth place with 26 points having played two games more than City.
Positive COVID tests robbed Guardiola of Kyle Walker, Gabriel Jesus, Ferran Torres and keeper Ederson for the first game of the new year.
There was also the matter of Benjamin Mendy breaking COVID protocols, although he was on the City bench.
Initially City looked vulnerable but when De Bruyne missed a sitter in the 15th minute it sparked them into life and Chelsea were swept aside with ease.
City are unbeaten in seven league games and have conceded only two goals in that run, scoring 14.
"After five or 10 minutes we found our rhythm," said De Bruyne, who was instrumental in City's best moments. "After that we played very well and took our chances at the right time.
"We play a bit differently this year but the team is finding the rhythm in the last month."
Chelsea manager Frank Lampard now faces the task of trying to pull his side out of a nosedive that has silenced all talk of a title challenge.
De Bruyne should have given City the lead when he was played in by a superb pass from Joao Cancelo but the Belgian dragged his shot agonisingly wide of the far post.
Three minutes later though City went ahead as Foden played the ball sideways to Gundogan who produced a silky turn before firing a right-footed shot past Edouard Mendy.
City doubled their lead in the 21st minute when De Bruyne threaded a pass in to Foden who finished clinically.
The wheels really fell of the Chelsea wagon in the 34th minute when De Bruyne headed a ball out and Raheem Sterling had half the length of the pitch at his mercy with Chelsea's defence desperately trying to reel him in.
Sterling looked to have over-elaborated as he was forced wide but eventually turned to thud a shot against the post with the ball rebounding to De Bruyne who coolly slotted home.
Chelsea enjoyed more possession in the second half with City content to play on the break but they looked a forlorn side and rarely tested City's American goalie Zack Steffen who was making his Premier League debut in place of Ederson.
The only blot on City's copybook was the late goal by Hudson-Odoi who turned in a cross from Kai Havertz.
Leicester move up to third place with win at Newcastle
Leicester City moved up to third place in the Premier League as second-half goals by James Maddison and Youri Tielemans secured a 2-1 victory away at Newcastle United on Sunday.
Substitute Andy Carroll's strike for the hosts set up a tense finale but Leicester were worthy winners.
They moved above Tottenham Hotspur with 32 points from 17 games played, one point behind co-leaders Liverpool and Manchester United, who have played one game less.
Maddison blasted Leicester in front in the 55th minute, and when the outstanding Tielemans produced a great finish to double the lead after 72 minutes it seemed that Leicester's seventh away win in the league was in the bag.
Carroll's first Premier League goal for Newcastle for 10 years offered a late twist.
"When we got the goal against us, we started panicking and stopped playing really. In general, we played well and the win is the most important thing," Tielemans said.
Leicester began well, and Maddison came close to giving them an early lead with a curling effort that fizzed just wide.
Manager Brendan Rodgers was livid when Jamie Vardy and Tielemans were guilty of over-elaborating once they had sliced open Newcastle shortly after, while Vardy also had a goal from a tight angle disallowed for offside.
Newcastle were well-organised without offering much in attack in a largely forgettable first half, but the hosts started the second half with greater purpose.
They were stopped in their tracks though when Harvey Barnes surged forward and slipped a pass to Vardy who held the ball up before teeing it up for Maddison to lash home.
Leicester's slick attacking football was evident again for their second goal as Marc Albrighton slid an astute pass inside towards Tielemans, who did not even need a touch before burying the ball past a helpless Karl Darlow.
Newcastle manager Steve Bruce sent on Carroll, and the big striker rewarded him almost immediately with a clinical volley -- his first league goal since returning to the club in 2019.
Suddenly the hosts came alive and Leicester were living dangerously at times until they were relieved to hear the whistle.
Newcastle's winless run in the league now extends to five games and they stay in 15th spot with 19 points.
"All game it was there and obviously when I came on, we got the goal and put the pressure on them so could have nicked something. It wasn't a great first half. It's hard this time of the year with all the games," Carroll said.
"We came out in the second half and played a lot better. I thought we deserved something."