The Chilean forward scored twice in a 2-0 win, catapulting the Gunners back into third place.
LONDON (AP) — Alex Sanchez's double eased Arsenal back into third place with a 2-0 win over West Bromwich Albion on Thursday, smoothing the north London team's pursuit of Champions League qualification after back-to-back draws.
Arsenal moved two points ahead of Manchester City, which was held by Newcastle on Tuesday, and four ahead of fifth-place Manchester United.
Securing a place in the top four of the English Premier League is the remaining target for manager Arsene Wenger, with Arsenal 10 points behind leader Leicester and only 12 points to play for.
"We are under permanent pressure," Wenger said. "Because Leicester is front everyone thinks we should have done it (won the title) ... but you can say that for everyone."
Arsenal fans with loftier ambitions are not satisfied with the 12-year drought without lifting the league trophy, and there was the unusual sight of thousands of empty seats for a rare Thursday night game at the Emirates Stadium.
Arsenal announces tickets sold (59,568 on Thursday) rather than the actual attendance but those supporters who did turn up didn't have to wait long to see a goal.
Sanchez received a pass from Aaron Ramsey in the sixth minute and spun past Sandro before picking a spot in the bottom corner of the net.
"It helped us to focus more on the way we played and not be anxious," Wenger said. "(Sanchez) is back — sharper, more confident."
And he curled in his 15th goal of the season directly from a free kick in the 38th past Ben Foster after his teammates in the defensive wall split for him.
With Arsenal enjoying more than 70 percent of possession, this is the type of game Arsenal should have secured a commanding scoreline. On other days, such as Sunday when Arsenal was held by Crystal Palace to 1-1, the team is made to pay for such wastefulness in front of goal.
"We haven't been up to that standard of late and it was important for us to put on a performance today — not just for our fans but for us as well," Arsenal midfielder Aaron Ramsey said. "We have been really frustrated with the way we have been playing but we have come back tonight ... maybe it's too little too late."
There were a few scares against a team only three places above the relegation zone.
Before Sanchez scored his second, only the crossbar preserved Arsenal's lead with Gareth McAuley crashing a header against the woodwork from James McClean's corner.
Later in the second half, Salomon Rondon lifted the ball over at the back post from a corner rather than nudging it over the line to force West Brom back into contention.
Arsenal was denied a couple of penalty appeals in the second half. Alex Iwobi went down after Dawson went in to challenge, and Mohamed Elneny also fell softly. Referee Jon Moss, who sanctioned Leicester striker Jamie Vardy for diving on Sunday, didn't brandish any cards this time.
It is Leicester's astonishing rise this season that has added to murmurs of discontent at Arsenal this season, although there were no open signs of revolt for the visit of 15th-place West Brom.
Three months ago, the Gunners were ahead of Leicester at the top of the standings on goal difference and now they are 10 points adrift.
"Of course we have regrets," Wenger said.