Arsenal's one change for the Chelsea derby

Ezri Konsa comes in for Cristhian Mosquera, who misses out through injury, as Arsenal host Chelsea at the Emirates Stadium in a lunchtime derby that both clubs will treat as an early marker for their season. Everything else stays as it was in the 1-0 win at Aston Villa, the clearest sign yet that Arteta trusts the group he has rather than feeling any need to rip it up after the transfer window shut.

Konsa steps in

Mosquera's absence forces the only tweak to the back line, and Konsa gets the nod to slot straight into a defence that has been doing its job quietly this season. There's no fuss made about it, no press-conference build-up quoted here, just a swap dictated by fitness rather than form. Bruno Guimarães is available among the substitutes, giving Arteta another option to change the shape of the game from the bench if the derby tightens up in the second half.

Chelsea shuffle their own pack

Chelsea have made alterations of their own, with Josh Acheampong involved in a reshaped lineup for the trip across London. The exact scale of Chelsea's changes isn't fully laid out before kick-off, but this is not a Chelsea side simply rolling out the same eleven from midweek.

Why it matters now

Early September derbies rarely settle anything on their own, but they set a tone. Arsenal, unbeaten and building on that Villa win, get to test whether their momentum survives contact with a genuine rival. Chelsea get an early look at where they stand against the club many expect to be scrapping with them for the top four, if not higher, come May.

The Emirates crowd will have their say long before full time, and Konsa's first involvement in a fixture this size will be watched closely, not because anyone doubts his ability, but because London derbies have a habit of finding a defender's weak moment inside the first twenty minutes.