It was the ecstasy and the ignominy.
For Manchester City, the joy of a scoreline that doubles up as a statement, courtesy of a surreal first 25 minutes, an emphatic addition to the list of memorable, magnificent eviscerations of the elite in recent years.
They had already scored six against Manchester United, Arsenal and Tottenham Hotspur this decade. Chelsea were an unwanted addition to that list.
But for Chelsea, it was an embarrassment. They were overwhelmed, out-passed, outclassed and out-thought, some elementary errors, tactical mistakes and poor individual performances combining to compound the gulf in class as they conceded six goals in a league game for the first time since 1991.
For Sergio Aguero, it was another landmark occasion. Few score hat-tricks against Arsenal and Chelsea in a career, let alone in the space of eight days.
His 15th City treble could have been a quintet, with an uncharacteristic miss from four yards and then a header that rattled the bar, but it was still a landmark occasion as he passed Eric Brook and Tommy Johnson’s shared record of 158 league goals for the club.
Remarkably, 25 have come in his last 16 home starts, and his first of the day ranked among his finest for City. He has rarely felt more potent.
If it all amounted to an endorsement of Pep Guardiola, who orchestrated a demolition without calling upon Leroy Sane and when benching David Silva for 75 minutes, it was an indictment of Maurizio Sarri.
While the watching Ole Gunnar Solskjaer looked glum, it was a result to suggest Manchester United are far likelier than a shambolic Chelsea to finish in the top four. A season that began so well is in danger of disintegrating.
Sarriball has rarely felt as ineffectual or misguided, or the Italian further away from realising his vision with this group of players. Jorginho’s failings as a defensive midfielder were exploited by a rampant City on a day when Chelsea’s porous rearguard could have benefited from having N’Golo Kante immediately ahead of them.
Following the second-half capitulation at Bournemouth, the world’s most expensive goalkeeper, Kepa Arrizabalaga, has now conceded 10 goals in the space of 124 minutes away from home.
City’s fast starters were swift to exploit that soft underbelly, even if a fourth-minute opener felt slow by their starters. It was a trademark goal with Bernardo Silva’s deflected cross falling for Raheem Sterling, cutting in from the left flank, to finish.
Silva was the provider, too, for Aguero’s strange miss. Guardiola sank to his knees in surprise then, but had much to celebrate before long. Having failed at the simple, Aguero succeeded at the spectacular, scoring from 25 yards.
Then Chelsea gifted goals, the Argentine latching on to Ross Barkley’s awful header to score and Ilkay Gundogan supplying a smooth finish after Antonio Rudiger’s misplaced clearance.
Aguero equalled Alan Shearer’s record of 11 Premier League hat-tricks from the penalty spot after Cesar Azpilicueta fouled Sterling.
The game’s other Argentinian striker, Gonzalo Higuain, drew an acrobatic save from Ederson, but his side were four goals adrift by that stage. Defensive deficiencies rendered a superstar striker an irrelevance.
Higuain at least completed the game, while Guardiola took mercy on Chelsea by removing Aguero and Kevin de Bruyne, but Sterling still added a sixth as City returned to the top of the table in style.