Despite Los Blancos' first half supremacy and two-goal cushion at half-time courtesy of Gareth Bale and Borja Mayoral, Los Legionarios were by far the better side during the second 45.
A heavily rotated Real Madrid forced Barcelona to wait 24 hours longer before having the opportunity to be crowned LaLiga champions after securing a 2-1 win over Leganes on Saturday evening.
Despite Los Blancos' first half supremacy and two-goal cushion at half-time courtesy of Gareth Bale and Borja Mayoral, Los Legionarios were by far the better side during the second 45. But the visitors were unable to capitalise on Darko Brasanac's simple finish shortly after the hour-mark to take anything away from the Estadio Santiago Bernabeu.
The results places the Champions League semi-finalists one point behind city rivals Atletico Madrid and means Barcelona must leave Deportivo La Coruna on Sunday evening with something to clinch the title this weekend.
The hosts assumed complete dominance from the outset, with Leganes struggling to put their foot on the ball for any extended period.
And Los Blancos' overriding supremacy provided a deserved tangible reward after just eight minutes as Bale found himself in the right place at the right time to toe home his 15th goal of the season.
Karim Benzema's initial effort was well blocked by an outstretched defensive boot before possession bounced into the path of the Welshman, whose acrobatic strike had just enough purchase to beat the advancing Ivan Cuellar to give Zinedine Zidane's outfit the perfect start.
After going ahead, Real Madrid continued to find themselves in the ascendency; however, from the resulting free-kick of a pacy Nordin Amrabat break, Miguel Ángel Guerrero flashed inches wide of Kiko Casilla's right-hand post; offering the hosts a warning that despite their dominance, Asier Garitano's men can punish sloppy defending.
But moments later, it was the hosts' turn to spurn a glorious opportunity as Mayoral found the ball at his feet with Leganes goalkeeper Cuellar wildly out of position, only for the young Spanish striker to see his effort cleared off the line by Unai Bustinza to keep his side's deficit to one.
And the difference on the scoreline came the width of the crossbar away from being reduced to nothing, as Amrabat, undoubtedly the player who had troubled Real Madrid most during the opening half-hour, clipped the top of the woodwork from a sneaky poke on the edge of the area.
However, on the stroke of half-time, mass confusion surrounded the Estadio Santiago Bernabeu as Mayoral flicked home what he thought was Los Blancos' second of the afternoon, only for the linesman to rule it out for offside.
But after a spell of deliberation while on opposite sides of the pitch, the officials elected that the 21-year-old was indeed onside, and referee Ignacio Iglesias Villanueva brought an end to the opening 45 minutes with the score at 2-0, much to the bemusement of the Leganes bench.
After the break, Real Madrid's tempo dropped considerably compared to that of the first half, and their lackadaisical approach proved costly shortly after the hour mark as Brasanac brought the visitors back into the contest.
The hosts' patched together defensive line seemed to switch off as Amrabat found space on the right-hand side of the area before the Watford loanee squared a simple ball across the face of Casilla's goal into the path of the unmarked 26-year-old Serb, who slotted home into an unguarded net from six yards.
After grabbing a goal back, Leganes looked the most likely side to find the net again, with the outfit from Madrid's outskirts seeing the majority of possession in the attacking third.
However, Los Legionarios were unable to take advantage of their ascendancy, and much to the dismay of captain Gabriel, who was shown a red card after the final whistle following an altercation with the referee, the clash ended with Los Blancos claiming all three points.