Las Palmas were relegated to the second division in the rain on the Canary Islands after an abysmal defeat to Alaves.
A frustrating first half had no clear cut chances for either side, with both restricted to shots from distance in their attempt to break the deadlock.
Paco Jemez made a double substitution at the break and his team started the second half brightly but 30 seconds proved pivotal as Peter Etebo hit the crossbar with a 25 yard free-kick, only for Alaves to go up the other end and take the lead.
Munir headed in Wakaso’s cross on the latter’s return to his former club, sparking angry scenes in the stands with Las Palmas fans marching out in protest.
Rather than responding, Las Palmas collapsed and their high line would punish them again as Munir added a second in acres of space as Alaves’ attackers raced through and queued up in the penalty area to score.
Munir wasn’t given the chance to complete a hat-trick though as his replacement, Alvaro Medran, notched a third with a diving header, again in space, from the edge of the box after Ruben Sobrino’s intelligent cut back cross.
As the rain poured down Sobrino turned to finisher as he scored with a header of his own in the sole minute of injury time.
Las Palmas: Raul Lizoain, Matias Aguirregaray (Nacho Gil, 46), David Garcia, Alejandro Galvez, David Simon, Javi Castellano, Peter Etebo, Alen Halilovic (Jairo Samperio, 46), Imoh Ezekiel (Hernan Toledo, 71), Vicente Gomez, Jonathan Calleri.
Alaves: Fernando Pacheco, Alexis, Rodrigo Ely, Martin Aguirregabiria, Ruben Duarte, Mubarak Wakaso (John Guidetti, 68), Manu Garcia, Tomas Pina, Ibai Gomez (Alfonso Pedraza, 68), Ruben Sobrino, Munir El Haddadi (Alvaro Medran).