The home side took the lead in the 16th minute when Duván Zapata rolled a pass across the goal and Josip Iličić backheeled into the bottom right corner. Both sides hit the woodwork but Spal turned things around in six second-half minutes.
Andrea Petagna leveled against his former club in the 54th and Mattia Valoti netted a solo goal shortly after. Atalanta laid seige to Spal's goal but the visitors held on for the win. They remained in the relegation zone but moved up to 18th, one point from safety.