By Rob Kelly at The Hawthorns
Arsenal slipped to their first Premier League defeat in seven games as West Brom scored twice in five first-half minutes to condemn them to defeat.
The game off to a sluggish start, with the hosts sitting back, ceding possession and keeping their defensive shape - but the Gunners took the lead just after the half-hour mark.
It came from a familiar source, with Mesut Ozil breaking a Premier League record by supplying an assist in seven consecutive games as he whipped in a free kick for Olivier Giroud to head home.
The platform was there for Arsene Wenger’s side to push on, but they soon found themselves pegged back as James Morrison found space from a free kick to poke the ball into the top corner.
It was a real setback for the Gunners, and it only got worse five minutes later when Mikel Arteta - on for the injured Francis Coquelin - diverted a James McLean cross into his own goal from close range.
It was a disappointing turnaround, but the visitors came flying out of the blocks after the restart as Ozil hit the post with a first-time shot.
Joel Campbell had a golden opportunity to equalise in the 68th minute when Santi Cazorla found him in space six yards out, but the Costa Rica international sliced his shot from close range.
Jonas Olsson then hit the bar at the other end with a close-range header, but it was Arsenal who remained on the front foot, desperately searching for a way back into the game.
They were handed a lifeline with seven minutes remaining when Chris Brunt hauled Alexis down in the area, but Santi Cazorla slipped as he took his penalty and sliced it over the bar.
That proved to be the final act of a frustrating afternoon for the Gunners, who will wonder how they left the Midlands empty handed.
SETTING THE SCENE
After last week’s tragic events in Paris, Wenger had stressed the role that football could play in focusing his players’ minds.
Laurent Koscielny and Giroud - both of whom were playing in the French capital that fateful night - were included in Arsenal team, but the manager made two changes at The Hawthorns.
Hector Bellerin returned after a groin injury to take the place of Mathieu Debuchy, while Kieran Gibbs - who rescued a point with his goal in the north London derby last time out - replaced Joel Campbell on the left flank.
That meant Alexis switched to the right, while French teenager Jeff Reine-Adelaide was on the bench for the first time in the Premier League.
With Manchester City in the evening kick off, Arsenal went into the game with the opportunity to go top of the table.
But while there was much at stake, a stirring pre-match rendition of La Marseillaise added a sense of perspective to proceedings.
The pattern of the game was set almost immediately, with the Gunners dominating possession and the hosts getting men behind the ball in an effort to frustrate them.
It made life difficult for Arsenal, and their task was further complicated when Francis Coquelin limped off in the 14th minute to be replaced by Arteta.
But Wenger’s side continued to press and probe, waiting for a chink in West Brom’s armour - and they got their reward just before the half-hour mark.
Ozil had been quiet until this point, but when Arsenal needed him he delivered - curling in a pinpoint free kick to find Giroud six yards from goal.
The France international has been in fine form of late, and he wasn’t going to miss from there, cushioning his header beyond the outstretched arm of Boaz Myhill and into the far corner.
Moments later, Gibbs curled a shot over the bar after a quick counter and the Gunners looked in total control - but out of nothing they were pegged back.
Once again, the goal came from a set piece - Chris Brunt delivering the ball into the box to find Morrison in space, and the midfielder was able to make contact and loop his shot into the far corner.
It was a real blow for the visitors, who had not appeared under any threat until that point and they would have been kicking themselves for allowing West Brom back into the game.
But things soon went from bad to worse when, five minutes from the interval, James McLean broke down the left and curled in a cross that Arteta inadvertently diverted past Petr Cech to put the hosts in front.
It was a bewildering change of fortunes for the Gunners, who went into the break with plenty to ponder.
Arsenal started the second period with the bit between their teeth, and nearly had their reward within 70 seconds when Ozil’s whipped first-time shot hit the post.
Wenger’s side continued to up the ante, pouring forward in search of an equaliser - with Alexis leading the charge.
The Chile forward may have played twice during the international break, but he remained a livewire presence in the visitors’ attack - and he soon created a chance for Gibbs, who saw his shot blocked by Morrison in the area.
Salomon Rondon went close at the other end 60 seconds later as the game burst into life, and as the game entered its final third Arsenal had a huge chance to equalise.
It came as Cazorla collected the ball outside the area, looked up and chipped the ball towards the onrushing Joel Campbell, who had just come on for Kieran Gibbs.
Brunt slipped in the area, offering Campbell a clear view of goal six yards out, but he sliced his shot and Myhill was able to collect.
Wenger’s side continued to pile on the pressure, but were nearly caught out when Jonas Olsson hit the bar with a close-range header that bounced down on to the line and into Cech’s hands.
With seven minutes remaining, Arsenal had their chance as Brunt pulled down Alexis in the area but Cazorla slipped as he went to strike the resulting penalty and sliced it over the bar.
It was a frustrating end to a disappointing afternoon for the Gunners, who must dust themselves down and pick themselves up ahead of the visit of Dinamo Zagreb on Tuesday night.
Referee: Mark Clattenburg
Copyright 2018 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source.