( CNN ) -- Without talisman Lionel Messi , Barcelona slipped to their second defeat in a week as a 1-0 reverse at Athletic Bilbao Sunday blew the Spanish title race wide open . Already qualified for the Champions League knockout stages , their 2-1 midweek loss to Ajax Amsterdam could be forgiven , but Iker Muniain 's 70th minute winner for Athletic has far greater significance . It was Barca 's first league reverse of the season and left them level on points with Atletico Madrid with arch-rivals Real Madrid snapping at their heels a further three points adrift . Athletic , who are unbeaten at their new San Mames stadium , have moved up into the fourth Champions League spot with the victory . Muniain might have put them ahead in the first half but he wasted a great chance from close range , while Barcelona offered little in reply . Brazil 's Neymar was kept quiet but just after half time he burst through only to be pulled back by home midfielder Ander Iturraspe , who was lucky to escape with a yellow card . But the men from the Basque country remained a constant threat and Markel Susaeta crossed for Muniain to slide home his decisive goal . A second should have followed but Gaizka Toquero headed a cross straight at Barcelona goalkeeper Jose Manuel Pinto , who made a reaction save . Barcelona coach Gerardo Martino flung on Sergi Roberto and Pedro as late substitutes , but to no avail . Messi was confined to the sidelines for the second time this season last month with a hamstring injury which is set to keep him out of action until January , missing at least two more La Liga games . Meanwhile in Italy , champions Juventus went three points clear of early pace setters Roma with a 1-0 win over Udinese Sunday . It took an injury-time header from Spain striker Fernando Llorente to grab the three vital points as he headed Stephan Lichsteiner 's shot past Zeljko Brkic . Juve had plenty of chances to wrap up their 12th win of the season and sixth in a row , but were frustrated by dogged defense and poor finishing until the last gasp strike . Earlier , Roma were held to their fourth draw in a row , 1-1 away at Atalanta . Napoli , who are in third , nine points adrift , travel to Lazio Monday . Fourth placed Inter Milan failed to make up ground as they were held 1-1 at home to Sampdoria . Renan scored a late leveler for Sampdoria after Fredy Guarin had given Inter an 18th minute lead at the San Siro .
Juventus lose second La Liga game of this season last month . Beaten 1 -0 by Athletic Bilbao at San Mames . Goal by Juventus in first half gives Bilbao famous victory . Juventus stay top in Italy with 1 -0 win over Udinese .