Alexis Sanchez scored twice as Arsenal tasted victory in the Premier League for the 500th time with a 2-0 win over West Brom at the Emirates Stadium on Thursday.
Sanchez made it six goals in his last six league games with a first-half double, his first a low drive from outside the box and the second a free-kick that deceived Albion goalkeeper Ben Foster.
Gareth McAuley hit the crossbar with a header in between the goals, but Arsenal were otherwise rarely troubled as they recovered from successive draws against West Ham and Crystal Palace to move above Manchester City into third place.
With four matches to play, Arsenal now hold a two-point advantage over City and are four clear of Manchester United in fifth on a night that saw them move closer to Champions League qualification against a backdrop of empty seats at the Emirates.
West Brom slip to 15th and have just one point and one goal from their last five league outings as their wait to mathematically secure safety from relegation goes on.
The Gunners took the lead inside six minutes when Aaron Ramsey - coming into the team along with Olivier Giroud and Per Mertesacker - fed Sanchez and the Chile international impressively turned Sandro before firing a fine shot into the bottom corner from outside the area.
McAuley made a crucial block to deny Mesut Ozil - a notable omission from the PFA Team of the Year that was announced prior to kick-off - while Arsenal's sole inclusion in that selection, Hector Bellerin, fired wide midway through the half.
West Brom almost levelled when James McClean whipped in a corner and McAuley's deft header had Petr Cech beaten, but cannoned off crossbar as the home crowd breathed a sigh of relief.
The Baggies were fortunate at the other end when Ozil collected Bellerin's cut-back and hit a rather tame shot that somehow slipped through the legs of Foster, with Craig Dawson well positioned to save his keeper's blushes with a block on the goal-line.
But Foster was punished for a mistake seven minutes before half-time. After Ramsey had been fouled by Claudio Yacob, Sanchez stepped up and struck a 20-yard free-kick that completely baffled Foster, who stepped away from the ball's path as the hosts moved into complete control.
West Brom made a double change at the break, with Salomon Rondon - the only player left out by Tony Pulis from the team that lost to Watford - and Jonas Olsson coming on.
McClean had a header saved for the visitors early in the second half, while Arsenal had penalty appeals from Alex Iwobi and Mohamed Elneny turned down by referee Jon Moss.
The game was almost put to bed when Sanchez played in Ozil, but Foster got down sharply to deny the Germany international and Iwobi had an effort saved as Arsenal continued to press.
For West Brom, Rondon could not react quickly enough to a threatening Craig Gardner corner that deceived Cech - snuffing out any hopes of what would have been an unlikely comeback.
Arsenal came close to a third when substitute Joel Campbell struck just wide and Olivier Giroud was thwarted by Foster as they settled for a two-goal victory.