Shkodran Mustafi says the Arsenal defence need to stay focused when they switch defensive systems, but insists they can use the adaptation to their advantage.

After a few games with a back four, the Gunners switched to a back three against Crystal Palace.

Sead Kolašinac returned to the team on the left, and Calum Chambers became the third centre-back.

Reporters asked Mustafi what the difference is playing the two systems. The German responded (via “In defence there’s a lot of differences. But it will probably take too long to explain the difference between a back three and a back four.

“It’s important to be focused because when you play a back four and then switch to a back three, it’s a different type of game. You have to cover different areas and there are different areas where you can play the ball. It’s important to be consistent and concentrated when you switch the system.

“On the other hand, it’s a strength when you can play two systems because the opponent never knows how we’re going to start or finish the game.”

For me, that sums up the strengths and weaknesses of changing the system pretty well.

If the Arsenal defenders can play both setups, it’ll give them a big advantage. Wenger can pick and choose which formation to play based on the opponent. Opposition managers won’t know for sure how we’re going to play, and even if they guess right, we can always change mid-game.

However, the drawback is the lack of consistency.

Often, players in the best defences talk about always knowing where their teammate is.

When you’ve played 100 matches with the same players in the same formation, you can guess what they’ll do. Currently, we seem to get a new back line every few games.

We’d never seen Chambers, Mustafi and Koscielny in a three before Thursday night.

We’d never seen Maitland-Niles, Monreal, Koscielny, Bellerín in a four before Arsenal played West Ham this month.

So you can understand why a couple of positioning errors allowed Crystal Palace to score twice.

Hopefully, things will only get better as the season goes on but I wouldn’t count on it.