Manchester City demonstrated their Premier League title credentials with a dominant 1-0 victory at champions Chelsea.
Kevin De Bruyne scored the only goal as Pep Guardiola's men suffocated Chelsea with their intensity to move six points clear of the holders after seven games.
Chelsea lost striker Alvaro Morata to an apparent hamstring problem in the first half and were second best to a City side denied when Thibaut Courtois saved from David Silva and then Fernandinho.
De Bruyne's left-footed strike from the edge of the area proved decisive against his former club, to give City a sixth win from seven games and inflict Chelsea's second loss of the season.
De Bruyne left Chelsea for Wolfsburg in January 2014 and moved to City for £58million 18 months later. He is proving his calibre after being deemed surplus to requirements under then Chelsea boss Jose Mourinho.
Antonio Conte's champions were the only side to beat City at home and away last season, but City had conceded just twice, dropping just two points, in their six prior games and not at all in September.
City's line-up showed the strength of resources, even with Sergio Aguero absent following his car crash in Amsterdam.
Chelsea were buoyed by Wednesday night's win at Atletico Madrid and started the brighter.
Morata twice went close. Nicolas Otamendi recovered to deny the striker as he latched on to Cesc Fabregas' pass and then Morata headed over from N'Golo Kante's cross.
City did not let Chelsea's defenders have the time on the ball.
The hosts avoided early calamity when Gabriel Jesus charged down Courtois' attempted clearance from Antonio Rudiger's back pass and the ball went wide.
Fabian Delph, again deployed at left wing-back, had an effort blocked by Rudiger and John Stones headed the resulting De Bruyne corner wide. Stones fell heavily and had his wrist bandaged.
Raheem Sterling was sharp in the first half and intercepted one Fabregas pass out from the back, but Andreas Christensen, again deputising for the suspended David Luiz, tackled the City forward.
Cesar Azpilicueta, pushed forwards to right wing-back to negate the threat of Leroy Sane, had a shot saved by Ederson, who claimed the resulting corner and launched a counter attack.
Sterling surged down the right but over-hit his cross with Silva and Jesus queuing up at the far post.
Sane and Silva next linked on the left and Courtois saved smartly from the Spain playmaker.
Morata departed clutching the back of his left leg, but instead of turning to like-for-like replacement Michy Batshuayi, Conte sent on Willian.
Courtois saved Chelsea again. De Bruyne's corner found Fernandinho, whose diving header was parried by the Chelsea keeper.
Fernandinho was booked for a foul on Hazard, who then stung the palms of Ederson after Fabregas' quick free kick.
Sterling caused havoc down Chelsea's left in the second half. Silva had an effort blocked by Marcos Alonso and then Sterling's pass was flicked away from Silva by Rudiger.
City took a deserved lead when De Bruyne played a one-two with Jesus and struck a thunderous left-footed shot which left Courtois with no chance.
Jesus next saw his side-foot volley from Sterling's cross headed off the line by Rudiger as City celebrated an important win.