Brighton ended a run of three consecutive defeats by holding a disjointed Arsenal to a draw at the Amex Stadium.
Pierre-Emerick Aubameyang curled in the opening goal following fine work from Alexandre Lacazette after just seven minutes.
The Gunners dominated the opening half hour and the Seagulls required two superb saves from goalkeeper Mat Ryan on Aubameyang to stay in the game.
Arsenal right-back Stephan Lichtsteiner then made a poor mistake, heading a long ball into the path of Brighton striker Jurgen Locadia, who rounded Bernd Leno to equalise on 35 minutes.
Mesut Ozil was replaced at half-time but the visitors failed to regain their early composure and rarely tested Brighton’s defence.
The hosts pressed for a winner, catching out a ragged Arsenal on the counter-attack, but Locadia and Solly March both missed promising chances.
Wednesday’s draw puts Arsenal into the top four but Chelsea are a point behind in fifth and face Watford at 19:45 GMT.
A statement substitution?
Arsenal boss Unai Emery and Ozil have had a curious relationship this season and the decision to substitute the midfielder for Alex Iwobi at half-time will only add to that intrigue.
Emery recently insisted Ozil has a future at the club and the former Germany international responded with an inspirational performance in victory over Burnley but could not exert the same influence here.
Yet he did not play badly and was far from the biggest reason why Arsenal let Brighton back into the game after a commanding opening spell.
Ozil may not have tracked back from the corner that led to Brighton’s goal but the poor positioning of Arsenal’s centre-backs and Lichtsteiner’s woeful header from Davy Propper’s speculative pass were more culpable.
Lichtsteiner was fortunate to not be replaced – his passing accuracy below 60% for much of the game before a late recovery to finish on 69.6%.
And without Ozil in the second half, Arsenal lacked creativity and were still vulnerable to Brighton’s counter-attacks, resulting in Emery having to use all of his substitutes by 70 minutes as Aaron Ramsey and Ainsley Maitland-Niles were sent on for Lacazette and Laurent Koscielny respectively.
Emery appears to want to challenge Ozil and has made plenty of shrewd substitutions to help his side surge in the second half but Iwobi did very little in Ozil’s place and removing the German was perhaps the wrong call here.
Brighton recover after worrying start
After relatively narrow defeats by Burnley, Chelsea and Bournemouth in recent weeks, it felt like Brighton would slip to a far heavier fourth-straight loss here in the early stages.
The Seagulls could not keep hold of the ball – Arsenal nearing 85% possession after the first 20 minutes – and their defence showed frequent lapses in concentration, allowing the Gunners to regularly carve through.
But Ryan was alert. Just before the opener, Aubameyang ran onto Matteo Guendouzi’s ball over the top and tried to chip the Brighton keeper, who stretched to tip it away, while the Australia international then made an excellent low save to his right once Aubameyang was put clear through by Lucas Torreira’s long pass.
At that stage, Brighton’s only real chance was when Glenn Murray thought he had bundled in an equalizer after scuffing his first-time effort, but referee Anthony Taylor penalized the striker for a foul on Leno.
Yet once Arsenal showed how vulnerable they were defensively for Locadia’s goal, Brighton attacked with increased confidence and came close to a late winner.
Captain Dale Stephens picked out March and then Locadia with two exquisite long passes in behind the Arsenal defence but the former lifted his chip well over the bar and the latter dragged his left-footed effort wide.