Real Betis secured a 3-2 win over Athletic Bilbao.
Joaquin said he is proud of the achievement and this might not happen again.
"It's the first hat-trick of my life. I don't think it's going to happen again. I've never been a goal-scorer throughout my career, so I'm really proud to be able to get three goals against a rival like Athletic. Considering my age, it's not an easy thing to do," Goal.com quoted Joaquin as saying.
Real Betis will now compete against Espanyol on December 15.