It was almost as if Arsenal were rubbing it in, replacing Myles Lewis-Skelly with Martin Zubimendi to join Declan Rice in their midfield and with Bruno Guimaraes unused among the substitutes.

Mikel Arteta had elite midfielders to spare. Xabi Alonso, meanwhile, finished this match with two right backs in Reece James and Malo Gusto trying to fill in centrally while trailing 2-1.

We know what went down on deadline day so do not need to repeat it in full here, but to summarise it in a sentence: Chelsea sold Enzo Fernandez and signed nobody.

That made Arteta's 67th-minute substitution in his own midfield all the more intriguing. Chelsea were offered the chance to potentially sign Lewis-Skelly by intermediaries in the summer. They were interested in bringing in Zubimendi for a reunion with Alonso. They looked at multiple other midfielders, from Bournemouth’s Alex Scott to Roma’s Manu Kone to Monaco’s Lamine Camara.

They signed none of those names. With Moises Caicedo still sidelined, Jordan Henderson not ready and Alonso seemingly lacking some trust in Valentin Barco – the 22-year-old Argentinian who arrived from sister side Strasbourg this summer – Chelsea started with James and Romeo Lavia. When Gusto replaced Lavia after an hour, it confirmed the latter has still yet to complete a competitive full 90 for this club.

It is a glaring gap which held Chelsea back here, and one which threatens to continue to haunt them until they get to January at least. They got £125million for Fernandez, which is mind-boggling money, but that big bag of cash is no help on the actual pitch when unspent.

Chelsea have made a habit of scoring early. They took the lead against Fulham after 31 seconds, Brighton after 219 seconds, and Arsenal after 77 seconds. If the team mentality suddenly needs to shift because they have something to protect, that is harder to do without the appropriate players. 

(Unlike Chelsea) Arsenal are all singing from the same hymn sheet 

Chelsea’s analysts had seen this goal from Arsenal before. It was a copy and paste from their Community Shield victory over Manchester City. Christos Tzolis moves inside from the right, passes centrally, Martin Odegaard meets it and scores with only the goalkeeper in his way.

Arsenal looked like champions who knew exactly what to do under Arteta, and Chelsea like challengers still trying to understand what Alonso wants from them.

It was a carefully orchestrated move from Arteta. Alonso’s centre backs were preoccupied, Maxence Lacroix with Riccardo Calafiori after the left back had charged forward into the inside channel and Wesley Fofana with Kai Havertz. Odegaard was able to drift inside to meet Tzolis’s pass which was dummied by Havertz and score beyond a helpless Emiliano Martinez.

Speaking of Martinez, had Robert Sanchez conceded Arsenal’s equaliser from Havertz, there would have been untold criticism on social media of the Spaniard. The Argentinian may have been ever so slightly unsighted, but he will know that he should not have been beaten so easily.

MacPhee's magic touch

Chelsea's set-piece coach Austin MacPhee had a plan for how to deal with Arsenal at corners.

When Arteta’s side won their first, Chelsea immediately sent four players up the pitch. Joao Pedro and Cole Palmer stood on the halfway line while Morgan Rogers and Pedro Neto were 15 yards deeper. 

It forced Arsenal to send four of their own men back to mark them and cleared the congestion in the box.

Do not be surprised if we see others copy this tactic soon.