But now it is only about John Terry versus Wayne Bridge - the former England captain against the man who refuses to play for his country.
Since news of Terry's affair with Bridge's former girlfriend, Vanessa Perroncel, broke at the end of January, Saturday's clash has formed the inevitable backdrop to an increasingly tawdry saga.
Head-to-head: All eyes will be on John Terry and Wayne Bridge's confrontation
Will the pair even shake hands? William Hill were offering 11-10 on Friday that no handshake will take place at any point during the match and 7-2 that all City players will shun Terry's outstretched hand. You could even get 10-1 for Bridge to get a card for a tackle on Terry.
The former Chelsea and England team-mates, who once called each other best friends, have not met in person since the saga exploded.
ODDS ON: SOMEONE HAD TO MENTION THE TACKLE. Will Terry and Bridge shake hands today? Yes 4-6; No 11-10No City player to shake hands with Terry pre-match 7-2All City players to show they are wearing 'Team Bridge' T-shirts 10-1Bridge to get a card for a tackle on Terry? Yes 10-1Terry to get a card for a tackle on Bridge? Yes 10-1 (William Hill).
Shortly before 12.45pm they will be forced to confront each other face to face and then, barring incident or injury, spend the next 90 minutes confined within the claustrophobic space of the Stamford Bridge pitch with Sky's television audience for company.
Mark Hughes, the former Chelsea striker and Manchester City manager, will be among guests. Will Richard Keys dare ask him how close he came to signing Chelsea's badge-thumping Terry and so bringing both players together at City? Team Terry and Team Bridge would then have been the one and the same.
Both Mancini and Ancelotti were at pains yesterday to play down the affair. The pair, who were Italy team-mates during the 1990 World Cup, have not spoken to each other ahead of the match.
Mancini said: 'It's not affecting the dressing room at all and it must be about just the game. Wayne is strong and he is a good man and has a strong mentality. If he is able to concentrate on the match, then that will be good for us.
'I think Wayne will play and will play very well. There should be only one motivation and that is to play well for the club. That is his only motivation.'
Ancelotti also shrugged off suggestions that the problems Terry has experienced in his private life have affected his form on the field.
He said: 'I don't see that his condition went down. I think he's in good condition and doing a good job for the team.
'He's in focus, has a good mentality and will stay in focus. had a fantastic season and will do until the end.'
State of mind: Ancelotti has backed Terry, who was at fault against Inter Milan
But what about the error that gave Kevin Foley a shot at goal in the Wolves match, or the poor positioning that allowed Diego Milito to step inside and score for Inter Milan in the San Siro on Wednesday? They were not actions of a Terry of old.
'In the last matches he made mistakes but everybody can do that,' said Ancelotti.
'His behaviour was good. He didn't have the best performances but he had good performances.'
Terry is still the same in training, too, according to his club manager, displaying the sort of light-hearted behaviour that is bound to irk Team Bridge.
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'He jokes, he is professional and knows when to joke and when to be professional,' said Ancelotti.
Tellingly, however, the other players 'never' laugh at their captain's expense.
For Ancelotti, publicly at least, private indiscretions have no impact on performance, whether in training or match play. But the Chelsea manager's familiar raised eyebrow of indifference and dry delivery was decidedly more fractious on Friday.
'I'm getting fed up with this,' he said when asked for the umpteenth time about the Terry-Bridge saga, retreating to Italian to air his frustrations.
Mancini is under a different type of pressure, with his side winning just six of 13 matches this calendar year and being eliminated from the FA and Carling Cups.
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He insisted his position isn't under threat, but added: 'I'm sorry because I wanted to win one trophy this season for the club and the squad and the supporters, but for now my focus is on the fourth position.'
For Ancelotti, Saturday is a 'good moment' to face City and compensate for the 2-1 loss in December, particularly as second-placed Manchester United do not play in the league this weekend owing to the Carling Cup final on Sunday.
He said: 'We want to keep four points clear of United. We know it will be a difficult game because the last game against City we lost. So we have to do our best in this match because we need to win.'
Emmanuel Adebayor is suspended for City, but Carlos Tevez is available after returning from compassionate leave following the premature birth of his daughter.
The striker has scored in his last three starts against Chelsea for three clubs - West Ham, United and City - but his form will be in question as he has missed 12 days' training with the club.
Ancelotti said: 'This is a good time to play City. We have some injuries but have a good condition of the other players. City's form has dropped but we've had the same. The past does not decide this game.'
It will be fascinating to see if past indiscretions do, in fact, decide the match.
As he faces nemesis Terry for the first time. Chelsea backing Bridge!SPORTSMAIL COMMENT: Wayne Bridge - weak men don't win World CupsMARTIN SAMUEL: Left back at home, Wayne Bridge let nobody down CHELSEA FC