Rafael Ramos picked up two late yellow cards to leave Almeria with 10 men in stoppage time.
"We had played six games and only taken a point, so we needed this," Arribas said. "And against this rival it feels even better."
Atletico Madrid leads the league entering the 32nd of 38 rounds and hosts Villarreal on Saturday. Barcelona is one point behind before hosting Betis. Real Madrid is three points adrift before it visits Real Sociedad.