Granit Xhaka loops the ball over the Palace backline to Alexandre Lacazette on the left inside the area, but the striker has strayed offside.

Image source, Getty Images

Palace have actually started the second half quite well and another decent cross from Patrick van Aanholt is just in front of Wilfried Zaha as he races in at the far post.

Patrick van Aanholt hits a shot onto Hector Bellerin to win a corner for Palace. It lands with Martin Kelly, but his shot on the turn lacks any power and Petr Cech stoops to collect it easily.

Image source, Reuters

And we're under way again - I wonder what the respective managers have had to say in the break?

Answers on a postcard, or to #bbcfootball, or text to 81111 please...

Alistair Bruce-Ball
BBC Radio 5 live at the Emirates Stadium

Remarkable first half from Arsenal. It's difficult to gauge how good they were though because Crystal Palace were so dozy and never got started. Wilshere and Ozil have been good in midfield but the first three goals were so poor from Palace's point of view. They have been terrible in this first half.

Mesul Ozil - 11 - touched the ball six times in the build-up to Alexandre Lacazette's goal to make it 4-0.

Image source, BBC Sport

And after Timothy Fosu-Mensah slams a long-range effort miles over Cech's bar, the whistle goes to end a half that Palace will want to forget very quickly.

Chris Kavanagh gives Granit Xhaka a talking-to after the Gunners midfielder appears to give him a bit of backchat.

Despite that, Xhaka takes a free kick from a long way out on the right, and he curls his left-footed effort a long way over the bar.

Petr Cech has had little to do until now, when, after some sloppy work from Ainsley Maitland-Niles, Wilfried Zaha's deflected shot forces Cech into a super stop, down to his right, with his left hand over the top of him.

Image source, Reuters

Patrick van Aanholt floats the ball into the Arsenal area and Bakary Saka's suspicious-looking chest down - possibly handball - falls at an Arsenal foot to be cleared.

Andrew Neill: No goals for Arsenal for a while now. What're they playing at?!

Henry: I am not liking this Arsenal performance! Wenger and the board will think we no longer need Mkhitaryan and Abaumayang.

Paul Wragg: Nacho Monreal has been subbed due to impending £70m bids from PSG, Barca and Real Madrid.

Granit Xhaka threads the ball through a few Palace legs from the byeline, but Alexandre Lacazette cannot get it out from under him and the beleaguered away side hoof the ball clear.

After a beautiful touch to bring a high ball down, Mesut Ozil loses the ball, but then works hard to get it back and keep Arsenal camped out in the Palace half.

They're not home and hosed yet...

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Ainsley Maitland-Niles replaces Nacho Monreal, who gets a rapturous ovation from the home fans as he trots off.

Image source, Reuters

Nacho Monreal looks troubled by a knock, and it looks like he will be off soon. Still, one goal and two assists for 32 minutes' work isn't bad...

Alistair Bruce-Ball
BBC Radio 5 live at Emirates Stadium

Roy Hodgson will be absolutely seething on the touchline here at the Emirates Stadium because Crystal Palace have been so dozy right from the start of this game. The first and third goals came from identical deep corners to find Nacho Monreal at the far post and Monreal had two or three men to pick out with his pull-back for the second goal.

Mesut Ozil and Jack Wilshere linked up beautifully for the fourth goal and it's exactly what Arsenal needed after their recent run of results but I wouldn't suddenly suggest everything is rosy in the garden because Palace have been awful with a capital A.

Image source, Reuters

Bakary Sako holds off Mohamed Elneny and gets a shot away that Petr Cech saves low to his right, but Wilfried Zaha, in space inside the area, might have been a better option.

It's not about those not here today - either coming or going - it's about those out on the pitch, and you feel that Arsene Wenger's selection today are making a bit of a point.