Arsene Wenger was denied victory in his 811th league game in charge of Arsenal as an 89th-minute penalty earned West Bromwich Albion a 1-1 draw at the Hawthorns.
Callum Chambers was adjudged to have handled a Kieran Gibbs cross when the ball hit him at close range and Jay Rodriguez converted to cancel out an Alexis Sanchez free kick that went in off James McClean six minutes earlier.
The point was enough for the home side, who had gone bottom of the table after Swansea's win at Watford on Saturday, to climb back above the Swans.
Alan Pardew's side had early encouragement when Matt Phillips crossed and Petr Cech dived to catch a Rodriguez header.
Moments later, Cech dropped a high ball but Jake Livermore's attempt was blocked before Arsenal attacked and an Alexandre Lacazette shot was deflected wide.
With a little over 15 minutes gone, Alex Iwobi shot over from the edge of the box and, after a scrappy spell, Sead Kolasinac fouled Rodriguez 25 yards out only for Chris Brunt to curl his attempt high over the bar.
That sparked Arsenal into action and Iwobi found space to fire in a shot that was parried by Ben Foster.
The visitors soon had to make an early substitution when Kolisanac took a knock and was replaced by Ainsley Maitland-Niles, while West Brom's Jonny Evans was booked for a heavy challenge on Iwobi.
Inspiration was proving hard to come by for either side, but Brunt and Phillips tried to provide some only for the latter's low cross to be easily gathered by Cech.
Rodriguez had a shot blocked in the opening seconds of the second half before Arsenal came forward through Lacazette, who won a dangerous free kick just outside the penalty area only for Sanchez to send his effort into the West Brom wall.
On the hour, shortly after Brunt had been booked for a foul, Iwobi fed Lacazette, whose strike was kept out by Foster.
Granit Xhaka and Lacazette teed up a half-chance for Sanchez with 20 minutes to go as Arsenal put pressure on the home defence, but his strike was blocked and the Baggies cleared.
Arsenal brought on Per Mertesacker on for Laurent Koscienly, with the home side introducing McClean for Phillips and Grzegorz Krychowiak for Brunt.
Iwobi then fired an effort straight at Foster as the final quarter of an hour approached before making way for Danny Welbeck with Wenger looking to add a late spark.
Allan Nyom came on for West Brom as Pardew looked to protect a point, but his side almost had the lead when Rodriguez had an effort parried by Cech and McClean's angled follow-up was charged down.
With a little under 10 minutes remaining, Sanchez was fouled by Craig Dawson, who was booked, to give Arsenal another dangerous free kick -- and this time his effort found a way in off the unfortunate McClean with Foster helpless.
But it wasn't enough to secure victory as Rodriguez kept his cool to salvage a point, with Wilshere booked for his complaints and Cech also receiving a yellow card after the final whistle.