Maarten Martens's goal 10 minutes from time was enough to earn AZ Alkmaar a 2-1 win at home to Valencia in the first leg of their Europa League quarter-final tie.
The hosts took the lead on the stroke of half time when Australian Brett Holman fired in a stunning acrobatic volley from a corner.
The Spaniards were level just five minutes after the break as Mehmet Topal met Alberto Costa's cross to power a header into the net.
Roberto Soldado nearly gave the visitors the lead on the hour, but his drive came back off the post.
Alkmaar grabbed the winner in the 81st minute as Martens was picked out by Holman before he converted past Diego Alves.
