Alexis Sanchez helps Barcelona down Espanyol

Barcelona extended their lead at the top of La Liga on Friday as they overcame stiff resistance from Espanyol to win the Catalan derby 1-0 at the Camp Nou.

Alexis Sanchez scored the only goal of the game midway through the second-half when he tapped home Neymar's pinpoint cross to score for the third consecutive game.

However, it was another frustrating evening for Lionel Messi as he failed to score for a fourth consecutive La Liga match.

Barca now lead second-placed Atletico Madrid by four points and Real Madrid by nine with both sides from the capital having played a game less.

The hosts were almost back to full strength after resting a host of first-team regulars for the 3-0 win over Celta Vigo in midweek as Gerard Pique, Javier Mascherano, Xavi, Andres Iniesta and Neymar all returned to the side, whilst Martin Montoya deputised for the injured Adriano at left-back.

However, the toll of five games in 13 days appeared to affect the Spanish champions as their build-up play was laboured in the first-half and they caused Espanyol very few problems.

Kiko Casilla was forced into an early save from Alexis Sanchez after nice work by Iniesta and Messi.

But it was the visitors who had the best chance of the half when Victor Sanchez sneaked in behind Dani Alves and Victor Valdes had to race from his line to turn the midfielder's effort behind.

Barca did come to life just before the break as Iniesta's volley from the edge of the area was parried by Casilla before Alves struck the post from similar range.

The pattern continued after the restart with Espanyol happy to sit 10 men behind the ball and wait for Barca.

Gerardo Martino's men nearly made the breakthrough on 54 minutes when Casilla produced a fine save to turn away Messi's flicked header.

Neymar then bent a stunning effort inches wide of Casilla's left-hand post as the pressure built from Barca.

And it was the Brazilian who finally unlocked the Espanyol defence as his wonderful low cross between the legs of two defenders left Sanchez with the simplest of finishes at the back post to register his seventh goal of the season.

Messi saw a free-kick fly just wide with nine minutes remaining as Barca went in search of the goal that would kill the game off.

Substitute Pedro Rodriguez ought to have doubled the advantage when he fired into Casilla's legs two minutes from time, but Barca held on to register their 10th clean sheet in 17 games this season.