Pizzi for Deportivo and Victor Casadesus for Mallorca each had an early tester on goal but neither player could find his respective target.
However, on the stroke of the half-hour mark Gama was set up by Valeron and he made no mistake to give Deportivo the lead.
Mallorca tried to hit back before the break but Emilio Nsue and Marti had efforts blocked by the Depor defence.
Just after the restart Javier Arizmendi had a strike on target but Daniel Aranzubia was alert to keep it out.
Marc Fernandez Gracia, on as a substitute, had a shot well saved by Aranzubia as he looked to change the game.
However, Depor held firm and took an important three points despite a late Giovani Dos Santos effort flying wide of the post.