The champions had looked short of ideas for more than an hour in Barcelona before midfielder Guti came off the bench to score a superb free kick in the 70th minute and striker Raul sealed the win two minutes later.
Barca, who were beaten 2-1 at home by city rivals Espanyol last weekend, can restore their seven-point advantage with victory at Atletico Madrid on Sunday.
Espanyol made the brighter start at the Olympic Stadium and almost scored on six minutes when Iker Casillas was forced into a reaction save from a glanced Roman Martinez header.
But neither side came close to breaking the deadlock until Guti, recently back from a lengthy injury layoff, replaced Wesley Sneijder just before the hour.
He won a freekick in a central position and although goalkeeper Carlos Kameni got a hand to his curled long-range effort, he could only deflect it in to the top left corner.
Raul doubled the lead soon after when he stroked Marcelo's pass low past Kameni from the edge of the area.
"We're just taking each match one by one and collecting the points as we go," Raul said in a television interview.
"I think Barca are in good shape -- they have some great players and a top coach -- but we are definitely making things difficult for them."
STYLISH DOUBLE
Barca lead the standings with 60 points from 24 matches with Real in second on 56 from 25 and Sevilla third on 47. Fourth-placed Villarreal (41) play at Betis on Sunday and Valencia, in fifth (39), host Real Valladolid.
Earlier on Saturday, Frederic Kanoute scored a stylish double to help Sevilla to a 2-1 comeback victory at Athletic Bilbao.
Sevilla enjoyed more possession in the opening stages but it was the home side who struck on 26 minutes. Andres Palop got a hand to Igor Gabilondo's low shot but the ball squirmed over the line into the bottom corner.
Kanoute produced a sublime piece of control to create the equaliser five minutes before the break. The Mali international took the ball down in the penalty area, shrugged off a defender and slammed the ball past Armando.
He twice went close before grabbing the winner just before the hour when he picked up a Ndri Romaric pass and drove the ball into the bottom left corner.
Sevilla return to the San Mames on Wednesday to play Athletic in their King's Cup semi-final second leg with the Andalusians leading 2-1 from the first leg.
