The writing was on the wall when the smallest player on the pitch scored with a header after just 80 seconds.
Let’s get it straight. City are the best team in Europe right now, they extended their own winning record to 18 games in all competitions and the scoreline makes it look far closer than it actually was.
The harsh truth was that City were much the better side, were guilty of taking their foot off the gas and, even though Arsenal battled, they never remotely looked like scoring and managed just one shot on target.
For far too long, Arsenal looked as if they were prepared to stand off, watch and admire Pep Guardiola’s champions-elect without ever getting close enough to put in a tackle.
Sterling was given so much space to nod home the only goal that it was hard to work out who was supposed to pick him up. It looked like it should have been Hector Bellerin.
City have turned visits to the Emirates into exhibition matches in recent seasons, such is their hold over Arsenal that it looks as if they have got into their heads like no other team has managed.
And to prove it, Arsenal have now failed to score in a fourth consecutive league match at home against the same opponent for the first time in their history.
That is obviously partly down to City’s brilliance as they pass and move their way through most teams but to show such little resistance in the first half hour was, quite frankly, embarrassing.
Embarrassing because it shows how far City are ahead of the rest. Embarrassing because Arteta looks to be intimidated by his old boss. And embarrassing because it was more of a case of damage limitation than an actual contest.
City played the game at their own pace and this has already become more of a title precession than a title race. But we should not lose sight of the fact we are watching one of the truly great teams in English football history.
It has long since stopped feeling strange when City start games without a natural striker because they are such a complete team that it feels any one of them can finish off a free flowing move.
Their opener was a typical example. Mahrez tricked his way down the right, cut inside and then teased a lovely cross which sliced Arsenal’s defence in half and Sterling nipped in to glance home.
City opened up Arsenal’s defence time and again with such ease that it was a miracle they did not conceded again. Sterling, Mahrez and Ilkay Gundogan all went close in what felt like one-way traffic before Arsenal finally began to come out of their shell.
Typically, it was Kieran Tierney, with a fierce 20 yard shot after 30 minutes, who turned the tide and showed that there were two teams in the game. Far too often they rely on their left back to give them lessons in heart and desire. The best thing you could say about Arsenal was that they kept the score down.
City eased off the in the second half, Kevin De Bruyne went tantalisingly close, Gundogan forced a good save from Bernd Leno while Joao Cancelo should have scored late on, but steered wide from close range.
Cancelo caught Rob Holding on his way through and the Arsenal defender was replaced by David Luiz as the home side used a concussion substitution as they ended up making four changes.
Maybe City were just saving energy for the Champions League or maybe they just make it look so easy.