A few weeks ago Arsene Wenger quipped, in reply to a question about Alexis Sanchez and speculation linking him with a move to Chelsea, that there was "only one team in London."
The Arsenal manager knows better than that, of course, and when he's not playing for the crowd he's spoken before about how having many derbies makes seasons a bit more difficult for clubs from the capital.
The Gunners face their second such game inside a week when they travel to Selhurst Park on Monday to play Crystal Palace. Sam Allardyce's team won four Premier League games in a row for the first time since 2015 before being beaten by Southampton on Wednesday, but having beaten Chelsea last weekend they won't be too worried about what is still a fairly brittle Arsenal outfit.
A draw against Man City and the win over West Ham have steadied what was a very unstable ship, but those two results are no proof that they're back on track. They still have some way to go to convince people they can match the 19-game unbeaten run from the first half of the season, making the need for three points against Palace all the greater.
There were encouraging signs against West Ham, though. None more so than a midfield combination which actually worked. Even taking into account how poor the opposition were, Wenger has to continue with Granit Xhaka and Mohamed Elneny.
Wenger has his favourites, players who tend to get picked when perhaps their form doesn't merit it, but after such a long spell without a win, it would be very strange to change a midfield duo that were instrumental in Arsenal's first Premier League victory since Feb. 11.
Elneny is never going to be one of the great midfielders of the game, but he provides the team with a reliable outlet due to his relentless energy and movement. And while he is criticised for not being the most ambitious passer, he understands that particular job is one for his partner, while his is to keep the ball circulating through midfield.
He completed 69 of 71 passes -- 99 percent -- against the Hammers on Wednesday night, enabling Arsenal not only to keep possession but to build momentum as they did so.
Xhaka, meanwhile, was the one who spread the ball wide, and sought opportunities to find the runs of Sanchez and Theo Walcott as they looked to cut in from the flanks. He ended up making 107 passes, and he has regularly got into triple figures for passes completed this season.
It used to be the remit of Santi Cazorla, and before him Mikel Arteta, to be the player with the most touches and the most passes, and it looks as if that baton has been handed over the 24-year-old.
The £35 million summer signing has had his critics -- not always justifiably -- because of his disciplinary issues, but his passing ability, and range of it, has been obvious from the get-go. The issue has been the lack of a partner who complements him properly, and there were signs that Elneny might be the man to do that over the coming weeks.
It's impossible to be definitive about that, simply because we haven't seen them play together often enough. That's something that's now in Wenger's hands though. He can rightly point to injuries, suspensions and international absences preventing him from achieving consistency of selection in midfield, but this time around he has none of those to contend with.
On the basis of what they did against West Ham, Xhaka and Elneny should start on Monday, and if they can combine the same way, Arsenal will have a good chance of taking the points they need.