The result of Sunday's Manchester derby between hosts City and rivals United could provide an indication as to which team will be crowned Premier League champions at the end of the season.
Both teams are currently outside the top three after picking up seven points from their opening four matches, but this weekend's derby offers a chance for both Manuel Pellegrini and David Moyes to make a major statement of intent.
The two managers will be involved in their first Manchester derbies - and their decisions will, of course, have a decisive bearing on which team prevails.
But they will need their key players to perform on the afternoon.
Here are the battles they will need to win:
Vincent Kompany v Robin van Persie
Robin van Persie made the decisive contribution in this fixture last season, scoring the last-minute free-kick winner which helped United pull away from the rest of the pack.
The Dutchman, who finished as last season's Premier League top scorer, currently has six goals from as many matches and will be determined to help United secure another memorable win at the Etihad Stadium.
Standing in his way will be Vincent Kompany, who returned to action for City in the Champions League this week.
After being out on the sidelines for a little while, Van Persie will fancy himself to get the better of the Manchester City captain.
Yaya Toure v Marouane Fellaini
A clash of the titans and arguably the most important battle of Sunday's Manchester derby, new United signing Marouane Fellaini can make himself an instant hero amongst the Red Devils' faithful by doing a job on Yaya Toure.
Manchester City's midfield powerhouse has been superb so far this season, scoring three excellent goals from his five matches of the campaign, and now has more license to venture forwards thanks to the acquisition of Fernandinho.
Expect some ferocious tussles between these two heavyweights.
Sergio Aguero v Rio Ferdinand
Sergio Aguero showed exactly what he could do to Manchester United last April, when he drifted past the United defence before firing the ball past David de Gea.
One of the defenders he floated past was Rio Ferdinand, who will be keen to make amends in this weekend's fixture.
Ferdinand will need to be at his imperious best to thwart Aguero, who is likely to be key to City's attacking play.
Jesus Navas v Patrice Evra
Jesus Navas is adjusting to life at Manchester City but has flattered to deceive so far.
However, the Spaniard has a great chance to kick-start his Manchester career by inspiring the Citizens to all three points against their local rivals this weekend.
In a straight race between Navas and Evra, there really will be no contest: the City star is one of the fastest players in the Premier League.
But Evra will use his experience and knowhow to frustrate his opponent.
Fernandinho v Wayne Rooney
Fernandinho has the unenviable task of keeping an in-form Wayne Rooney quiet this weekend.
The Brazilian will be expected to drop back and pick up United's playmaker to prevent him working his magic in the final third of the pitch.
It's a big ask for the 28-year-old, but these are the matches why City splashed out £30m for his services.
Rooney scored twice in this fixture last season - don't be surprised if he does the same this weekend.