Arsenal’s defence was a mess against Liverpool.

For the first goal, Hector Bellerín, playing on the wrong side, failed to stop a cross coming in from Gomez, but no one in the back three did anything to try and stop Firmino’s free header into the Arsenal net.

Mané’s finish was a very good one for Liverpool’s second, but that doesn’t excuse Monreal failing to get tight to him, and Oxlade-Chamberlain jogging back.

If you were wondering what was going on, and how Arsenal could put up with defending so dire, you weren’t the only one, as Arsène Wenger himself decided enough was enough and switched to a back four.

Problem solved? Unfortunately not.

The second half defensive performance was just as bad, and Hector Bellerín could’ve done much better again as he was dispossessed as the final man in his own half (!) after an Arsenal corner, and Liverpool quickly countered and scored.

For the final goal, Rob Holding raced out of position but failed to win the ball, leaving Bellerín and Koscielny alone, and Koscielny didn’t do enough to track the run of Sturridge in behind him.

Mustafi is rumoured to be on the way out, and was benched today for a 21-year-old and a left-back. Gabriel has already left. If Arsenal sell, it’s difficult to see how the Gunners can put together any half-decent defence before the window closes.

But it starts with picking the best players available. Mertesacker should’ve played against Stoke and could’ve improved the horror show today. Mustafi, going or not, should have played. Kolašinac, a fantastic addition to Arsenal’s left side, should be on Arsenal’s left side, not at centre-back. Or on the bench.

Sead especially shouldn’t be dropped for the defensive liability and offensive disappointment that won’t take £180,000 a week from Arsenal. On today’s evidence, and last week’s evidence, and the overall evidence of the last six years, Oxlade-Chamberlain does not deserve it whatsoever.

Arsenal have until Thursday to sort out their defensive issues, or this could happen over and over again as the season goes on.