The visitors are also reeling at the moment, albeit from an off-field decision as opposed to on-field struggles, as they prepare to reluctantly sever ties with Manchester United-bound boss Ruben Amorim.
Match preview
The City faithful ought to have arrived at the Vitality Stadium with a spring in their step on Saturday, as news filtered through that Arsenal had slipped up in the Premier League title race at Newcastle United, giving the champions the chance to move eight points clear of the Gunners.
However, Guardiola's off-colour team would deservedly end the day off of their Premier League perch on account of a shock 2-1 loss to Bournemouth, where the ever-dangerous Antoine Semenyo and Evanilson registered before Josko Gvardiol's consolation effort.
With Liverpool able to do what City could not and recovering from a deficit at home to Brighton & Hove Albion, Guardiola's side find themselves two points adrift of the Merseyside titans in the runners-up spot in the top-flight table after their astonishing 32-game unbeaten run in England's top flight crashed and burned.
City's South Coast collapse came just a few days after their EFL Cup dreams were extinguished at the home of Tottenham Hotspur, but the 2022-23 Champions League winners have made a near-unblemished start to continental matters this term, putting four past Slovan Bratislava and five past Sparta Prague after their 0-0 with Inter Milan on matchday one.
Excluding penalty shootouts, the Citizens have gone a record 26 games without a normal time or extra-time defeat in the Champions League, but Amorim's Sporting could hardly be facing the Premier League champions at a better time before their much-coveted manager begins his own Manchester adventure.
Answering the Old Trafford call after the delayed yet inevitable departure of Erik ten Hag, Amorim will be officially sworn in as Man United's new head coach following the November international break, and victory on Tuesday would be the perfect way to endear himself to the Red Devils faithful.
Despite claims from Portugal that some of Sporting's high-profile stars are upset with the 39-year-old's decision, the Primeira Liga powerhouses have been going about their business regardless and welcome City to the Estadio Jose Alvalade on a sensational run of form.
Indeed, Sporting dismantled Estrela Amadora 5-1 on Friday to make it 10 wins from 10 games at the start of the 2024-25 Primeira Liga season - needless to say, they hold an unassailable lead at the top of the table - and their Champions League record is not half-bad either.
Amorim's side share City's record of seven points from their opening three games, beating Lille and Sturm Graz either side of a 1-1 draw with PSV Eindhoven to sit eighth in the 36-team table, five places behind Guardiola's side on account of their inferior goal difference.
Now bidding to equal their longest-ever unbeaten run in the Champions League/European Cup - going four without defeat in the early 1980s - Sporting reunite with Man City on the back of their 2021-22 last-16 battle, where Amorim's team were embarrassed 5-0 at home before restoring some pride with a second-leg goalless draw at the Etihad.
Sporting Lisbon Champions League form:
W
D
W
Sporting Lisbon form (all competitions):
W
W
W
W
W
W
Manchester City Champions League form:
D
W
W
Manchester City form (all competitions):
W
W
W
W
L
L
Team News
Guardiola's fear that he may only have 13 players available for Bournemouth did not quite come true, as all of Savinho, Jeremy Doku, Kyle Walker and Kevin De Bruyne were part of the matchday squad after exiting the infirmary.
However, the City boss has confirmed that defensive duo Ruben Dias and John Stones are out for a "little bit of a long time" with unspecified concerns, joining Rodri (ACL), Oscar Bobb (leg) and Jack Grealish (unknown) in the visitors' medical bay.
Neither De Bruyne nor Savinho - who was stretchered off with an ankle injury in the loss to Tottenham - made it off the bench at the Vitality, though, and Walker is surely a candidate to drop out for Rico Lewis after being run ragged at the weekend.
As for Sporting, Amorim should only be missing two stricken troops in the shape of 22-year-old defender Eduardo Quaresma (muscle) and long-term absentee Nuno Santos, who is expected to miss the rest of the year with a knee injury.
Responsible for a fabulous four of his side's five goals in the embarrassment of Estrela, Swedish sensation Viktor Gyokeres has allegedly been identified by the Man City hierarchy as an ideal acquisition should Erling Haaland ever seek pastures new.
The 26-year-old has already banked an outrageous 20 goals in 17 games this season, and he has found the back of the net in all four of his home starts for Sporting in European competition.
Sporting Lisbon possible starting lineup:
Israel; Inacio, Diomande, Debast; Quenda, Braganca, Hjulmand, Araujo; Trincao, Gyokeres, Goncalves
Manchester City possible starting lineup:
Ederson; Lewis, Akanji, Ake, Gvardiol; Silva, Kovacic, Gundogan; Doku, Haaland, Nunes
We say: Sporting Lisbon 2-2 Manchester City
Many eyes will be on the battle between two scintillating Scandinavians in Gyokeres and Haaland on Tuesday, and the Lisbon affair should live up to the billing as Amorim aims to go out on a high.