After an early display of questionable defending, Arsenal regrouped themselves and regathered their purpose to overcome Valencia and take a 3-1 first-leg lead.
Valencia will take an away goal back to Mestalla, but Marcelino’s men trail Arsenal 3-1 after the first leg of the Europa League semi-final.
Alexandre Lacazette scored twice as Arsenal came from behind to beat Valencia 3-1 at home in the first leg of the Europa League semi-final.
Mouctar Diakhaby headed Valencia into an early lead at Emirates Stadium on Thursday but within 14 minutes the Gunners had turned the tie around.
Lacazette first finished off a swift counter-attack involving Mesut Ozil and Pierre-Emerick Aubameyang before heading home Granit Xhaka’s cross to put Unai Emery’s men in front.
And the Spaniard, a three-time winner of the competition with Sevilla, will take a two-goal lead back to former club Valencia for next week’s second leg after Aubameyang struck late on.