Bernd Leno produces a brilliant one-handed save to tip over a Mbaye Diagne header but the whistle is blown for a foul by a West Brom player anyway.

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

That's just a piece of brilliance from Pepe.

The mistake West Brom make is they allow him to come in on that left foot and get the shot off.

But take nothing away from Pepe, it's accurate, has got power and goes into the far corner, a really good finish.

That was a really good finish by Emile Smith Rowe, his first in the Premier League.

Feel for West Brom, though, they had looked good and maybe even the most likely to score before that suckerpunch.

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

The two youngsters combined really well there.

Saka has been a constant threat down the left and has given Furlong a torrid night so far.

It was a really good run from Smith Rowe, a little bit of static defending from West Brom, but he showed good technique to put it into the corner.

A good goal, really well worked from Arsenal.

Willian floats the ball into the box and finds Calum Chambers, whose cross is deflected behind for a corner. The Baggies deal with the delivery from the set piece but Arsenal win another in quick succession. This one is played low into the box but it runs through and West Brom get rid.

Dani Ceballos is fouled by Matt Phillips and Arsenal have a free kick in a reasonably dangerous position, some 30 yards from goal.

Mohamed Elneny then has a go from distance with a well-struck effort but puts it too close to Sam Johnstone.

First shot on target for the Gunners.

That's not a good sign as Mohamed Elneny surges forward, slows down before stretching his arms out wide as if to say to his team-mates 'where are my options?'. In the end he passes to Emile Smith Rowe but the attack breaks down.

Darnell Furlong slides in on Bukayo Saka inside the area, the challenge looks clumsy but he gets the ball.

Image source, Getty Images

Matt Upson
Former England and West Ham defender on BBC Radio 5 Live

Conor Townsend has started so well on that left-hand side. West Brom must be thinking if they keep asking questions of this Arsenal side then something will drop to us eventually.

Matheus Pereira again tries his luck from distance but fires a well-struck shot into the sidenetting.

Callum Robinson is suddenly in behind the Arsenal defence but smacks his shot against the bar. The flag then goes up, he was offside anyway.

Diego Pele: Mikel Arteta has 10 more games to save his job. He should be bold and innovative. Arsenal should be playing young and upcoming players rather than Dani Cellabos and Martin Odegaard who are not going to be here next year.

Matheus Pereira has four goals and two assists so far this month and once again he's looking West Brom's most dangerous player. He's buzzing around a fairly static Arsenal defence, causing problems with his movement.

West Brom have four players waiting inside the box as the visitors attack. The ball is worked to Callum Robinson. whose shot is blocked before Matheus Pereira bends a brilliant effort from outside the box just wide.

Better possession from Arsenal now as they appear to settle into the game. They're not quite showing a desire and determination to bounce back after their Europa League exit, though. Quite pedestrian so far.

First opportunity for Arsenal as Bukayo Saka gets in behind on the left and puts in a decent cross that is half cleared before Nicolas Pépé balloons an awkward effort on the half volley well over.