Arsene Wenger's record-breaking 811th Premier League match as a manager ended in frustration and disappointment as West Bromwich Albion scored a controversial 89th-minute equaliser to rescue a point at The Hawthorns this evening.
It looked as though Arsenal had edged a largely uneventful affair when Alexis Sanchez's free kick deflected in off James McClean for an own goal, but it proved to be that all of the action was reserved for the closing stages.
Calum Chambers was harshly penalised for a handball just four minutes later, and Jay Rodriguez stepped up to the resulting spot kick and fired it down the middle to rescue a point for the Baggies in the final Premier League game of 2017.
The result means that West Brom's winless run extends to 19 in the top flight and 20 across all competitions, whereas Arsenal miss the chance to move back to within one point of the top four and will now begin 2018 with a three-point deficit to make up.
The Baggies had slipped down to bottom of the table as a result of Swansea City's victory over Watford on Saturday, but despite their torrid run of form Alan Pardew's side started the match on top.
Rodriguez had the first effort on target after only seven minutes when he planted a header from Matt Phillips's cross towards goal, and Petr Cech almost gifted the hosts an opener moments later when he spilled the ball inside the box.
Jake Livermore was unable to capitalise on the mistake, though, and Arsenal immediately went up the other end and saw two Alexandre Lacazette efforts blocked before they could trouble Ben Foster.
It wasn't until shortly before the half-hour mark that the Gunners tested the West Brom keeper for the first time, and even then it was a routine stop for Foster as he collected Granit Xhaka's long-range strike.
Foster almost made a mess of another save moments later, though, misjudging Alex Iwobi's effort and having to readjust in midair to claw it away for a corner.
The Gunners were missing the creativity of Mesut Ozil, though, and West Brom more than held their own as a largely uneventful and unexciting first half came to a close.
The second half started in a similarly pedestrian fashion until Arsenal finally began to up the tempo on the hour mark, with Lacazette working space to shoot before drawing a smart save from Foster with his powerful low drive.
Lacazette scored twice when the two sides met in the reverse fixture, and the Frenchman came close again moments later when he got a toe to Sanchez's pass to steer the ball narrowly wide.
The relative flurry of action continued a minute later when Sanchez cut inside from the left flank and went for goal himself, but Foster looked to have it covered as the ball slammed into the side-netting.
It took until the 77th minute for West Brom to have their first clear chance of the contest when Arsenal's defenders backed away from Rodriguez, allowing him to sting the palms of Cech from the edge of the box.
The bulk of the action came in the final seven minutes, though, beginning with Arsenal's opener when Sanchez won a free kick on the edge of the box and then dispatched it himself as his effort went through the wall, deflecting off McClean in the process before flashing past a helpless Foster.
It went down as a McClean own goal, and the poor efforts of the West Brom wall looked like costing Pardew's side a hard-earned point before referee Mike Dean controversially pointed to the spot after Kieran Gibbs had diverted the ball onto the arm of Chambers.
Chambers could have done nothing about it and Arsenal were incensed by the decision to award a penalty, which Rodriguez duly tucked down the middle to spoil Wenger's landmark day.
The point is enough to lift West Brom back off the bottom of the table and to within three points of safety, although they are still winless under Pardew and are still waiting for their first league triumph since August.
Arsenal, meanwhile, move up a place to fifth but are still three points off the Champions League places on a night which saw Wenger surpass Sir Alex Ferguson as the most experienced Premier League manager of all time.
Both teams will be back in action in midweek, when West Brom take on West Ham United and Arsenal host Chelsea.
West Brom (4-4-2): Foster; Dawson, Hegazi, Evans, Gibbs; Phillips (McClean, 72'), Livermore, Barry, Brunt (Krychowiak, 72'); Rodriguez, Robson-Kanu (Nyom, 75')
Arsenal (3-4-3): Cech; Chambers, Mustafi, Koscielny (Mertesacker, 72'); Bellerin, Wilshere, Xhaka, Kolasinac (Maitland-Niles, 37'); Iwobi (Welbeck, 74'); Lacazette, Sanchez
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