Atletico Madrid kept their Primera Division title bid going with another 1-0 win but they were made to work hard for the victory by a stubborn Rayo Vallecano side battling for their lives at the other end of the table.
City rivals Real Madrid won at Real Socieded earlier in the day so Atletico came into the game third in the table behind Real and second-placed Barcelona, the last of the three title contenders to play today against Real Betis.
Diego Simeone's side responded to Real's victory and kept up the pressure on Barca thanks to a second-half goal from substitute Antoine Griezmann.
It gave Atletico their fourth straight 1-0 win in all competitions and sent them into their crucial Champions League semi-final second leg against Bayern Munich in Germany on Tuesday on a high.
With that game in mind Simeone, who had to watch from the stands as he served the first of a three-match touchline ban, made seven changes to his starting line-up and it disrupted Atletico's rhythm.
The hosts almost made the perfect start, though, courtesy of some terrible defending by Antonio Amaya in the fifth minute. The error was seized upon by Angel Correa, whose shot from the right-hand side of the penalty area looked destined for the far bottom corner of the net until Juan Carlos produced a brilliant save to touch the ball wide.
Thereafter, Rayo, who remain just two points above the relegation zone, actually had more efforts at goal than Simeone's team but a lack of quality in the final third prevented them from capitalising.
Adrian Embarba curled a shot wide from the edge of the area before warming Jan Oblak's palms with another strike. In between Amaya headed the ball over the crossbar from a corner.
Koke was introduced by Atleti at half-time but Rayo remained in the ascendancy during the early stages of the second half.
An excellent first touch from Javi Guerra to control Bebe's driven, low cross saw him create a shooting opportunity for himself 10 yards out but Oblak saved easily.
The Slovenia goalkeeper then had to help the ball over the crossbar as Quini's cross threatened to drop into the net.
Simeone had seen enough and after 54 minutes he brought on Griezmann and Fernando Torres. It proved a master stroke as Griezmann immediately pounced on a loose ball, controlling it on his chest before hitting a left-foot shot into the bottom corner of the net from the edge of the box.
Atletico had finally stamped their authority on the match and Torres should have doubled the lead in the 70th minute after he was put through on goal by Griezmann, but he shot straight at Carlos.
Koke then flashed a shot wide with the outside of his right foot shortly afterwards.
Rayo were still a threat on the break though and it took some typically solid defending from the hosts, together with a couple of commanding claims from Oblak to relieve the pressure, to see out the game and hold on to a precious three points.