Celso Borges fired home a 70th-minute penalty as Deportivo La Coruna ended a run of three games without a win with victory at Rayo Vallecano on Friday night.
Celso Borges: Penalty proved the difference
Borges hit a rising spot kick past home goalkeeper Antonio Tono after Abdoulaye Ba was booked for a foul on Sidnei in the box.
Borges had opened the scoring for the visitors in the 10th minute when he forced home a shot from six yards but the hosts equalised 11 minutes later when Alberto Bueno fired home.
Starting the night in 10th place, Rayo had high hopes of bouncing back from last weekend's defeat at Atletico Madrid with a home win against their struggling opponents.
Carrilho and Ba both had good chances in the opening minutes before Borges' opener against the run of play gave Deportivo an advantage they barely deserved.
Bueno struck to level matters and he could have grabbed a second just before the half-hour mark when his header from 12 yards was caught by Fabricio Ramirez in the visitors' goal.
Raul Baena flashed a header just wide before the break for the hosts but Deportivo ended the first period on top with both Borges and Jose Rodriguez coming close in quick succession.
After a quiet start to the second half the home side began to take control with Ramirez saving well from a Bueno volley and Luisinho clearing well under pressure from Roberto Trashorras.
Deportivo grabbed their chance from the penalty spot and as Rayo pressed for an equaliser it was the visitors who got chances to extend their lead.
Isaac Cuenca brought two saves in quick succession out of Tono then another Cuenca effort five minutes from time brought an even better save out of the increasingly busy home keeper.
Home chances proved few and far between as the visitors held on to the lead with some comfort and claimed three potentially crucial points in their battle to avoid being sucked into another relegation fight.