La Liga PHOTOS: Barca fall six points behind Real

Barcelona's poor run away to Real Sociedad continued when the champions were held to a 1-1 draw at Anoeta on Sunday and slipped six points behind La Liga leaders Real Madrid before next week's 'Clasico' against their arch rivals.

Former Real Madrid academy player Willian Jose headed Real Sociedad ahead in the 53rd minute after a torrid first-half performance by Barca but Lionel Messi levelled in the 59th following a magnificent display of skill by Neymar.

Barca enjoyed some luck when Sociedad's Juanmi headed home after Carlos Vela had curled a shot off the underside of the bar and saw the goal wrongly ruled offside, while Mexican forward Vela hit the woodwork again late on.

Barca have not won away to Real Sociedad since 2007 although this was the first time in five league games at Anoeta that they had avoided defeat.

Luis Enrique's side are second in the standings on 27 points, six behind Real Madrid and level on points with Sevilla in third. Atletico Madrid are fourth on 24 after winning 3-0 at Osasuna, while Real Sociedad are fifth on 23.

Emboldened by a run of four straight wins in the league and their imperious recent record over Barca at home, Real Sociedad dominated the first half, testing Marc-Andre ter Stegen twice in the first 10 minutes, while Vela, Mikel Oyarzabal and Xabi Prieto each fired narrowly wide of goal.

Barca were limited to one chance before the break, a wayward distance effort by Luis Suarez, although Neymar forced a save from Geronimo Rulli from a stinging free kick just after the restart.

La Real found the opener minutes later thanks to the persistence of Vela. He chased down Javier Mascherano in the area and was thwarted by Ter Stegen but the loose ball was nodded back towards goal by Jose and in past a helpless Gerard Pique.

Barca hit back with their first incisive attack of the game, Neymar twisting his way past defenders down the left and squaring to Messi, who flicked the ball up before burying it past Rulli on the half volley.

The game suddenly opened up and either side could have won it. Vela's deadly curler came close to crossing the line and replays showed Juanmi was clearly onside when he turned in the loose ball.

Barca broke quickly and Denis Suarez rounded Rulli but saw his shot cleared off the line by Asier Illarramendi.

Mascherano glanced the resulting corner just wide and beyond an outstretched Suarez, while Vela sent a potent volley spinning off the far post.

"I feel very positive because we've got a point from a game that was practically impossible to get anything from," said Enrique.

"Real Sociedad won almost every ball and every battle and had more chances every ball so the fact we got a point is almost a miracle."

Villarreal slipped to sixth after a surprise 2-0 defeat at home to Alaves.

Villarreal felt the strain of returning to action less than 72 hours after their Europa League game away to Zurich and were beaten by two early goals from Alaves's Ibai Gomez and Victor Camarasa to surrender their unbeaten home record.

Celta Vigo beat winless Granada 3-1 in Sunday's other game.