Neither side created much in torrential rain in Andalucia, with Real Sociedad defender Inigo Martinez testing Alex Remiro as the best chance in the first 45 minutes.
La Real have just about edged the second half as the game was flipped on its head on the hour mark.
Spanish international Martinez was initially shown a straight red card for a handball inside the box before that decision was eventually overturned by VAR and downgraded to a yellow.
However, the original penalty still stood, with Oyarzabal taking full advantage to slam home past Unai Simon from the spot.
Y Oyarzabal no falló 🎯
— Sphera Sports (@SpheraSports) April 3, 2021
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