After such a positive start, Ralph Hasenhuttl will be under no illusions as to the cut-throat nature of the Premier League following back-to-back defeats against West Ham and Manchester City.
On Sunday afternoon, Southampton knew they would be punished if they gave the champions an inch - but they just couldn't keep their heads once Pierre-Emile Hojbjerg had equalised.
The Dane was then sent off with just five minutes left of normal time.
Things had already started to go very wrong for the hosts, James Ward-Prowse turning the ball into his own net before Sergio Aguero wrapped things up.
Though the Saints must have smelled blood in the wake of City's own run of poor form, they weren't able to capitalise.
It was arguably Pep Guardiola's side's most important game of the season, especially with Liverpool having won in such resounding fashion against Arsenal.
City are back and it all makes for a mouth-watering clash with the Reds on Thursday night.
However, spare a thought for Southampton, who are now back level on points with 18th-placed Burnley courtesy of the Clarets' own win over West Ham.
Try as they did, they couldn't find a way through a City midfield rejuvenated by the return of Fernandinho.
City fans weren't happy with Austin
The Brazilian doesn't always get the credit he deserves but he was sorely missed during his period on the sidelines.
He might have been set for another, too, with Hojbjerg making a late challenge on him and Charlie Austin having got away with another poor tackle.
Whatever referee Paul Tierney thought of the incident, the away fans were not happy and made their feelings quite clear to Austin.
As he was soundly booed by the City supporters when he was replaced by Shane Long, the striker couldn't restrain himself from reacting, lifting two fingers before departing the pitch.
As The Sun point out, the 29-year-old could now find himself facing a ban.
Many football fans appreciate how Austin always wears his heart on his sleeves, but it seems likely the FA will take a dim view of his behaviour.
A three-person panel will review footage on Monday morning.
Of course, it's possible that there was something else to provoke such a strong response.
When Troy Deeney was seen making a similar gesture against Chelsea earlier this year, he avoided punishment and was just "warned of his future conduct", per an FA statement.
Do you think Austin deserves a ban? Have your say in the comments.