Less than a month ago, Chelsea were being discussed in the same breath as Man City and Liverpool as title challengers, having won eight of their opening 11 Premier League games.
Such is the relentless pace being set by Saturday's opponents that a 10-point gap has now opened up between the two sides, though, with Chelsea paying the price for a recent dip in form.
It was not until November 24 that Maurizio Sarri suffered his first Premier League defeat as a manager - the longest a new boss has ever gone without losing in his debut season in the competition - but they go into this weekend having now lost two of their last three.
The 3-1 humbling at Tottenham Hotspur could be put down to coming up against another top team in good form, but Wednesday's 2-1 reverse at the hands of Wolverhampton Wanderers was a particularly disappointing result.
Newly-promoted Wolves had picked up just one point from their previous six league games and were coming off the back of successive defeats to Huddersfield Town and Cardiff City, but they came from behind at Molineux to inflict a shock defeat on Chelsea.
The harsh reality of the Premier League today is that two defeats in the space of 11 days will be ruthlessly exploited by those at the top of the table, and another loss this weekend could see any lingering hopes of a title challenge extinguished once and for all.
On the flip side, victory could breathe new life into those hopes by proving that they can beat the best, and it is more than two years since Sarri suffered back-to-back league defeats as a manager.
The Italian also remains unbeaten at Stamford Bridge as Chelsea boss, winning nine of his 12 home games in charge across all competitions. Indeed, including the tail end of last season Chelsea are now unbeaten in 15 home games, stretching back more than eight months.
Three of their last five home games in the league have seen the spoils shared, though, and Chelsea will this weekend be looking for back-to-back home league wins for the first time since mid-September.
Should they achieve that then there may be a glimmer of hope that it will not be just a two-horse race for the title, and more immediately it would see them keep their place in the top four amid some fierce competition from London rivals Tottenham and Arsenal.
Recent Premier League form: WWDLWL
Recent form (all competitions): WDLWWL
Not since 2002 have the defending Premier League champions beaten Chelsea at Stamford Bridge, but Guardiola's Man City looked the best equipped to break that streak.
Only last year's eventual centurions have ever amassed more points after 15 games of a Premier League season than City's current crop, reaffirming their status as one of the very best teams English football has ever seen.
The major difference between this season and last is the level of competition; after 15 games of 2017-18 they were eight points clear of the chasing pack and already being hailed as the champions elect, whereas this time around Liverpool are providing a much more stubborn challenge.
The Reds may not have been as scintillating as City so far, but they remain just two points adrift of Guardiola's side and could even leapfrog them in the table when they take on Bournemouth in the early kickoff on Saturday.
Beginning a match in second place would be an unfamiliar feeling for this City side and, having applied the pressure on Liverpool by opening up a five-point gap on a couple of occasions within the past week only to see that swiftly cut back down to two, the boot could be on the other foot this weekend.
Few will doubt the champions' ability to deal with that pressure, although their very recent form has not been quite as emphatic as we are used to seeing from the all-conquering Citizens.
Having been forced to come from behind twice en route to a Champions League draw with Lyon, City were then a little laboured in their win over Bournemouth before surviving a late scare to overcome Watford at Vicarage Road in midweek.
The crucial theme there is that they keep winning, though, and Guardiola's side are chasing an eighth successive Premier League victory this weekend, as well as a 19th from their last 22 league outings.
A small glimmer of Chelsea hope may come from the fact that all of Man City's dropped points have come away from home this season, but they are unbeaten on the road in the league since January and should they extend that run on Saturday then they would set a new club record of 15 top-flight away games without defeat.
Indeed, records seem to be tumbling on a weekly basis for this City side and they will be one of few teams in recent years to travel to Stamford Bridge as fairly comfortable favourites to win this weekend.
Recent Premier League form: WWWWWW
Recent form (all competitions): WWWDWW
Guardiola is expected to make changes galore throughout December, but he should field close to his first-choice team for this match with the likes of Aymeric Laporte and Raheem Sterling likely to return to the starting lineup.
Ruben Loftus-Cheek scored in that match and was Chelsea's best performer, so he will be hopeful of keeping his place in midfield ahead of Mateo Kovacic and Ross Barkley, the latter of whom is back in contention after an ankle problem.
Chelsea possible starting lineup:
Kepa; Azpilicueta, Rudiger, Luiz, Alonso; Kante, Jorginho, Loftus-Cheek; Pedro, Giroud, Hazard
Man City possible starting lineup:
Ederson; Walker, Otamendi, Laporte, Delph; Gundogan, Fernandinho, Bernardo; Mahrez, Jesus, Sterling
Head To Head
This will be the second time that these two sides have met this season, having also faced off in the Community Shield in August. Man City ran out 2-0 winners at Wembley courtesy of Aguero's brace.
Indeed, City have won each of the last three contests against Chelsea - including 1-0 triumphs home and away last term - and could record four successive victories against the West Londoners for the first time in their history this weekend.
Chelsea have lost two of their last three home Premier League games against City - the same number as they suffered in their first 18 such matches against them in the competition - and another defeat on Saturday would consign them to back-to-back top-flight home defeats at the hands of City for the first time since January 1955.
We say: Chelsea 1-1 Man City
Chelsea have had a bit of a wobble in recent weeks, but they have been strong at home this season. It is perhaps foolish to back against City winning any and every game on their current form, but Stamford Bridge will provide one of their tougher tests this season.