But after the perceived wisdom of tactical decisions and the pattern of the game had been dissected, there's one subject that refused to go away: Kevin De Bruyne's performance.
The Belgian outshone compatriot Eden Hazard, scoring the only goal in what proved a match-winning display from the City man.
And De Bruyne used to be a Chelsea player. Four years ago, he was starting the 2013/14 campaign under Jose Mourinho after a successful loan spell with Werder Bremen in the Bundesliga. Within six months, he was back in Germany, this time permanently, when Chelsea sold him to VfL Wolfsburg.
Far from repeating his impressive loan form when back at the Blues, De Bruyne's short spell in Mourinho's squad was disappointing. He struggled to impress, with game time limited as he fought for a place with Hazard, Willian, Oscar and Andre Schurrle all ahead of him in the pecking order.
At Wolfsburg, De Bruyne would become a £54 million player, with his performances convincing City to splash out a club-record fee just 18 months after his Stamford Bridge departure.
It's been a stick to beat Chelsea with ever since, and De Bruyne's showing in that convincing 1-0 defeat has added to it all the more.
The Belgian isn't alone here, however. Chelsea have made a habit of selling players seemingly too early in their careers, only for them to succeed elsewhere. Take Nemanja Matic, who first left in 2011 to join Benfica as part of the deal to sign David Luiz before Chelsea re-signed him in January 2014.
With an army of loan players across Europe, the expectation is more players are likely to join the list.
So how many more players alongside De Bruyne could challenge Chelsea's starting XI? We've put together a team of former Chelsea stars who are still active elsewhere to see whether the decisions to sell them were right or wrong in the long run.
Those who left on permanent deals, even with buy-back options, are considered for selection. Those who are only away from Stamford Bridge on loan, even if the expectation is that they depart in time, are not considered to be part of Chelsea's past.
We're also judging the past players on their impact and ability now rather than when they were at Chelsea—for example, Didier Drogba is not in the equation despite his legendary status in west London
We've attempted to go with manager Antonio Conte's likeliest side here, so while the Italian has opted for a 3-5-2 at various points this season, 3-4-3 remains the dominant formation—for now, at least.
There's a big debate about which players should be getting starts at Chelsea this season, notably with Andreas Christensen's emergence. Judging by the manager's team selection in the biggest matches, however, the below is based on what we think Conte's preferred XI is.
GK: Thibaut Courtois
DEF: Cesar Azpilicueta, David Luiz, Gary Cahill
MID: Victor Moses, N'Golo Kante, Tiemoue Bakayoko, Marcos Alonso
ATT MID: Pedro, Eden Hazard
STR: Alvaro Morata
Active Past XI
Now for the players who are no longer at Chelsea, of which there are plenty.
Given the changes Conte has made at Stamford Bridge in the past year, we think it's only fair to match up like-for-like because we are judging things on the state of play. That means lining them up in a 3-4-3 formation also.
GK: Petr Cech, Arsenal
This will probably be the simplest decision to make in this list. Petr Cech was the Chelsea No. 1 for a decade before he was pushed out by Thibaut Courtois, so for that reason alone, it means there isn't an abundance of past Blues goalkeepers of note who are doing the rounds.
Asmir Begovic will have something to say about that, but even now, the Bosnian isn't in the same bracket as Cech.
RCB: Nathan Ake, Bournemouth
When he was recalled early from his loan on the south coast last season, Blues fans got excited thinking Nathan Ake was going to be given an opportunity by Conte. He was part of Chelsea's dominant youth sides coming through the ranks, and fans enjoyed watching him mature.
In the FA Cup semi-final against Tottenham Hotspur last season, Ake put in a perfect performance, but it didn't prove enough in Conte's eyes, with the Dutchman being sold to Bournemouth this summer.
Our feeling is that move was made on the back of Christensen's return from a two-year loan spell with Borussia Monchengladbach, with space unavailable for two inexperienced defenders. Either way, it was disappointing to see such a talented defender depart.
CB: John Terry, Aston Villa
From the young to the old. Where Chelsea can be criticised for allowing Ake to leave, the time was right for John Terry's exit at the end of 2016/17. The former captain had probably outstayed his welcome by a season or two.
Now 36, his best days are gone, and in terms of their style, Terry's presence arguably held Chelsea back. It was only when he was injured last year that Conte changed his system, and it made the Blues champions.
Terry's inclusion here says much for Chelsea's transfer dealings in more recent times. There aren't many defenders out there the club has allowed to leave too early, with Ake bucking the trend more than anything else.
LCB: Filipe Luis, Atletico Madrid
In the same way Terry forces his way into this XI, Filipe Luis is out of position. The Atletico Madrid man is used to more of a left-back role, but we have had to reposition him to complete the back line.
Again, that's largely down to there being few defenders of quality who have left Chelsea and are still playing. That could change in the next couple of years, with Kurt Zouma on loan at Stoke City. And if Christensen doesn't get enough game time, he may well look elsewhere himself.
RWB: Juan Cuadrado, Juventus
Were we picking this team of ex-Chelsea players based on what they achieved at Stamford Bridge, Juan Cuadrado would get nowhere near it. The Colombian spent a painful six months as a Chelsea player at the back end of 2014/15, struggling to fit in.
He was then loaned to Juventus for two years before his move was made permanent this summer. And it has been a good transfer for him, with Cuadrado looking more like the player Chelsea thought they were signing.
When Conte came in, the belief was Cuadrado would become his right wing-back, but it never transpired. That role went to Victor Moses, yet it must be said Cuadrado has done a good job of rebuilding his reputation in Serie A.
CM: Nemanja Matic, Manchester United
The Serb's transfer has divided opinion this season. On one side of the argument, there are those who are shocked Chelsea could ever sell a player to major rival like Manchester United; then there are those who look at the deal as good business. The £40 million Chelsea received from the Red Devils for a soon-to-be 29-year-old effectively got them the 23-year-old Tiemoue Bakayoko.
That's not bad at all for a club accused of lacking foresight with their transfer policy, regardless of Nemanja Matic's ability in the middle. Now it's about a waiting game to see whether the move works better for Chelsea or United.
CM: Oriol Romeu, Southampton
The temptation here was to go with Nathaniel Chalobah as our midfielder alongside Matic. He was the young hope from the academy, and fans wasted little time in announcing their fury at his transfer to Watford this summer just gone.
That's fine and has its merits, as Chalobah has shown in his early performances for Watford that he can be a Premier League player. But he's behind someone like Oriol Romeu, who has experience playing at the highest level with Southampton for the past few seasons.
He's a different midfielder to Chalobah too. Romeu is more cerebral and, in that sense, would complement Matic's skill set.
LWB: Ryan Bertrand, Southampton
It seems Southampton have done well out of Chelsea in recent years, with Ryan Bertrand another former Blue they have on their books. Unlike Romeu, though, there's a solid argument to suggest Bertrand would be getting into the Chelsea side.
His competition would be Marcos Alonso, who is the only recognised left wing-back at the club. But it's about more than just a lack of numbers; Bertrand is a fine player, and his ability to get up and down the wing would be a major asset along with his defensive capabilities.
RAM: Kevin De Bruyne, Manchester City
Survey the landscape of those players deemed surplus at Chelsea, and De Bruyne stands out. He's the one who could put up the strongest fight to usurp Hazard as Chelsea's best player were he still wearing the club's colours.
The success of his move from Chelsea has been all about De Bruyne. He risked a lot to join Wolfsburg, and fired by his self-belief and a desire to prove his doubters wrong, the Belgian has become a bona fide world-class talent.
Chelsea's loss is very much City's gain.
LAM: Mohamed Salah, Liverpool
Now part of Jurgen Klopp's attempts to restore the glory days at Anfield, Mohamed Salah is another player with a backstory not too dissimilar to De Bruyne's. He was burned at Chelsea under Mourinho, moving to AS Roma on loan before making a permanent switch to the Italian capital in 2016.
He did much to restore his reputation and, on the back of his Serie A form, received a career-defining move to Liverpool. He's started well as part of the Fab 4 attacking unit under Klopp, but can he sustain it and progress to reach De Bruyne's level? That's the level he has to hit.
STR: Romelu Lukaku, Manchester United
The Belgian is a strange case. He was loaned to West Bromwich Albion and Everton while at Chelsea and scored goals aplenty. But put him in Chelsea blue, and he would cramp up, seemingly burdened by the expectation of playing for the club.
It was for that reason his sale to Everton in 2014 could hardly be criticised. Lukaku simply hadn't done enough to show Chelsea otherwise.
Given how he's started life at Manchester United this season, however, it seems Lukaku has got over that mental block and that there's an elite maturity about him. He's scored in nine of his 10 United games, clocking up 12 goals in all competitions already. Keep that strike rate up, and he would surpass the magical 20-goal mark before Halloween.
Chelsea's main striker these days is Alvaro Morata, and it's difficult to split the pair in terms of what they offer.
NB: Diego Costa remains a Chelsea player until January. Therefore, he was ineligible for consideration here.
There are some notable names in the Active Past Players XI that raise eyebrows about Chelsea's transfer dealings. We have already discussed De Bruyne, but the likes of Lukaku, Salah, Ake and Bertrand are also players who could offer something to Conte's side.
Equally, though, aside from De Bruyne and Lukaku, it's difficult to label any of these as being world-class. Look through the XI and it has a feel of being compiled by good squad players, but not outright starters.
Lukaku and De Bruyne sprinkle a little stardust in the way big names do in the Carabao Cup and early rounds of the FA Cup. They give just enough to convince a team they can perform well, with the others being the unit that provides a platform for them to succeed.
Chelsea's starting XI has much more about it. There's a balance, for one, but there is also a mix of individual talent that can turn matches and win league titles.
Switch to a 3-5-2, however, and that may not always be the case, as Chelsea found to their detriment when Pep Guardiola's City picked them off in that 1-0 defeat at Stamford Bridge.