The Portugal international scored twice in the opening 20 minutes to give the Spanish giants a hard-fought victory on Saturday, despite the visitors' late pressure.
Real Madrid were let off the hook by Duje Cop's missed penalty as Cristiano Ronaldo scored twice in an unconvincing 2-1 win over Sporting Gijon at a sodden Santiago Bernabeu on Saturday.
La Liga leaders Madrid were without star man Gareth Bale, who has been ruled out for up to four months with an ankle tendon injury, but appeared comfortable enough as talisman Ronaldo came to the fore in the soaking capital.
The Portugal superstar netted twice inside 18 minutes, opening the scoring from the spot after Lucas Vasquez - deputising for Bale - was felled in the area, before adding a second with a thumping header.
However, Gijon were gifted a lifeline before the break when Carlos Carmona profited from some slack play by Luka Modric.
It appeared as though a further twist was in store when Gijon were awarded a penalty in the 78th minute, but Cop fluffed his lines from 12 yards as Madrid hung on for the three points.
Zinedine Zidane's men consequently up the ante on Barcelona, who play at Real Sociedad on Sunday, with Luis Enrique's side - who host Madrid in the first Clasico of the season next week - seven points adrift of the leaders.
The visitors started well and almost broke the deadlock in the first minute, but Carmona prodded just wide from close range after a clever reverse pass from Moi Gomez.
Real took full advantage of that let-off shortly after, though, as Vazquez jinked past Isma Lopez to draw the foul in the area and Ronaldo slammed the resulting penalty into the bottom-right corner.
Ronaldo threatened again without succeeding a few moments later, but he did not have to wait much longer to double his tally - meeting Nacho Fernandez's brilliant left-wing cross with an emphatic header in the 18th minute.
Despite their defensive deficiencies, Gijon looked lively going forward and they gave themselves a lifeline 10 minutes before the break.
Modric's sloppy pass was intercepted in midfield and Gijon worked the ball down the left before Carmona directed Lopez's cross into the bottom-right corner with a hopeful flick of his right foot.
Gijon continued to see plenty of the ball after the break, but Real should have restored their two-goal lead just before the hour mark when Karim Benzema headed Vazquez's inch-perfect cross straight at Diego Marino.
Real began to tighten their grip on proceedings thereafter as they started passing forward with more purpose in an attempt to curb Gijon's belief.
But they needed a slice of luck 12 minutes from the end as Cop screwed his penalty wide of the top-right corner after Nacho fouled Victor Rodriguez in the area.
Real needed Keylor Navas to be alert shortly after to palm away Cop's close-range effort and Zidane's men held on for a scrappy win to throw down a gauntlet for Barcelona.
