City will have only a few supporters at Jubilee Oval on Sunday evening but fans across the whole country will be rooting for them because they see Erick Mombaerts's side as the one with the best chance of saving the competition.
Another victory for the rampaging Sky Blues, you see, would just about kill the A-League as far as the destination of the premiership goes.
The champions go into their Round12 clash against second-placed City with a commanding six-point advantage.
Steve Corica's side have dropped only five out of 30 points this season (Sydney have had a bye) and are playing competently and consistently enough to suggest that they could justifiably see themselves as strong enough to overcome an opponent that was well beaten in last weekend's derby.
Yet when you consider that the A-League is struggling for bums on seats and television viewers due in part to the extreme weather conditions across Australia that have affected the overall quality of play, the last thing it needs is a victory for the home team that would give the Sky Blues an almost unassailable lead.
There is a suspicion that Sydney, as one of the most experienced teams in the league, have yet to hit their peak this season.
They are brimming with confidence and know-how and are showing enough quality that sometimes they give the impression they can go into a higher gear whenever they need to.
They also are capable of getting a result even when they are not at their best as they did at the weekend in Wellington.
Phoenix and Sydney played out an entertaining 2-2 draw at the 'Cake Tin' and the draw was probably a fair result.
Yet if one team deserved to win it had to be Phoenix who were never intimidated by their respected rivals and were deprived of victory by two soft goals.
Sydney, as we all know, always find a way to win or not lose which of course is the mark of a champion team.
There is more than halfway to go but they also are the sort of team that are unlikely to throw away a nine-point lead, particularly in such a brief league as ours.
Melbourne City are not so consistent. They are capable of producing a kind of game that is pleasing on the eye but they occasionally will disappoint their fans with a dismal performance that, not for the first time, brings into question their big-match temperament.
City will try to overcome their derby blues when they put their season on the line on Sunday but they will not be the only organisation hoping for a shock result in a confrontation that should draw a big crowd at the much-loved ground.
The rest of the league no doubt will be watching the match with bated breath.
The clash no doubt will be billed as a battle royal between the top two teams in the league that have served up the best football so far this season.
The contest will also provide a fascinating duel at a distance between Adam Le Fondre and Jamie Maclaren, the two 'goleadores' who are leading the goalscoring race.
The Englishman has scored 11 goals from 10 matches to the Australian's 10 from seven and all eyes will be on the two dreaded strikers in their last assignment of the year.
The strikers' value to their team's cause cannot be overstated and no doubt both coaches will stress to their respective defenders the importance of stopping these natural goal poachers from causing their usual brand of damage.
No prizes for guessing which one of the two marksmen will have the support of the neutrals.
