Paulo Gazzaniga returned from suspension, as he started for Rayo Vallecano in their 2-0 defeat at Alcorcón.
The Saints keeper served a one-match ban in his loan club’s 2-1 home win over Levante a week earlier, but was back in the side for their latest Segunda División clash on Saturday.
Rayo had looked on course for a point against their fellow strugglers, but Alcorcón scored twice late on, through Ivi and Victor Pérez, to take the points.
The result leaves Gazzaniga and his teammates 14th in the table, ahead of their final four matches of the season, five places above the relegation zone, but only three points clear of it.
Rayo now face another big clash on Friday night, as they host Gimnàstic Tarragona, who currently occupy the final spot in the drop zone.