Jay Rodriguez’s controversially awarded late penalty denied Arsenal the chance to put pressure on the Premier League top four as they were held at West Brom.
It looked as though the Gunners had secured victory when Alexis Sanchez’s 83rd-minute free-kick beat keeper Ben Foster via a heavy deflection off James McClean.
But six minutes later referee Mike Dean judged Calum Chambers had intentionally handled when Kieran Gibbs tried to lift the ball over him, and Rodriguez fired the spot-kick past Petr Cech.
That made for a dramatic conclusion to a largely uninspiring game with few clear-cut chances.
Arsenal move three points behind fourth-placed Liverpool while West Brom climb off the bottom of the table on goal difference.
Was it a penalty?
Arsenal’s players protested both at the time of the incident and after the final whistle, when Cech was booked and Wenger appeared to say something to Dean.
A day ago, Southampton defender Maya Yoshida was deemed not to be at fault when he handled the ball against Manchester United, but there was no such good fortune for Chambers.
With Arsenal just moments away from securing victory, former Gunners full-back Gibbs’ attempt to push the ball past Chambers struck the arm of the defender. Chambers had little time to move his arm out of the way, but the referee judged it to be international.
That left Wenger and his players aggrieved just minutes after they had taken the lead rather fortuitously when Sanchez’s free-kick took a big deflection to wrong-foot Foster.
Before that, the visitors rarely troubled the Baggies backline, though Alexandre Lacazette went close twice.
And the late controversy meant they missed the chance to really close on the Champions League places, with a match against second-placed Chelsea to come on Wednesday.
Baggies earn point but lack bounce
As unfortunate as Arsenal were to concede late on, West Brom were fortunate to come away with anything from a display that appeared focused on defending.
Before the penalty, only Rodriguez’s second-half strike that stung the palms of Cech had the home crowd off their seats.
It is now no wins in 19 matches for Alan Pardew’s side, equalling the longest such run in the Premier League since Aston Villa’s sequence ended in January 2016.
The Baggies will have another chance to end that run on Tuesday when they play West Ham.
West Brom are at the Hammers’ London Stadium on Tuesday, and the Gunners host London rivals Chelsea on Wednesday.