Barcelona stumbled for a third straight match in its quest to defend its Spanish league title after losing at Real Sociedad 1-0 Saturday, letting Atletico Madrid and Real Madrid tighten the race even further. Mikel Oyarzabal headed in Sociedad's goal in the fifth minute, and goalkeeper Geronimo Rulli protected the lead with two saves of Lionel Messi's late efforts. Barcelona's failure to win at Anoeta for a sixth consecutive season came after Atletico fought back at Espanyol to win 3-1, and Cristiano Ronaldo led Madrid's 4-0 rout of Eibar. Two rounds ago, Barcelona was nine points clear after a draw at Villarreal. Now, after losses to Madrid and at Sociedad, Barcelona's lead has dwindled to three points over Atletico and four over Madrid with six rounds left. Barcelona hadn't gone three league games without a win since May 2014 and hadn't lost two straight rounds since November of last season. "We had built up a cushion of points so we could, let's say, allow ourselves to have some setbacks," Barcelona's Andres Iniesta said. "And now we have allowed about all we can." Barcelona coach Luis Enrique rotated his squad with the visit to Atletico in the Champions League Wednesday looming. Regular second-choice midfielders Arda Turan and Rafina got starts, while Munir El Haddadi filled in for the suspended Luis Suarez, the club's top scorer. Sociedad got a great start when 18-year-old Oyarzabal headed Xabi Prieto's excellent cross beyond the reach of Claudio Bravo. Sociedad then settled in and limited the work of Rulli, who came through with key stops. "We never said the league was over," Luis Enrique said. "We now have a great chance to show that we are indeed the best team in the world." Bottom-side Levante was beaten 1-0 by Real Betis in the late match. Juve 9 points clear In Milan, Juventus moved provisionally nine points clear at the top of Serie A as it came from behind to beat fierce rival AC Milan 2-1 Saturday. Inter Milan kept alive its slender hopes of securing a Champions League spot with a 1-0 win at 10-man Frosinone, which hit the woodwork three times. Mario Mandzukic wiped out Alex's opening score in the first half, and Paul Pogba secured the win for Juventus after an hour. Milan had chances but goalkeeper Gianluigi Buffon was resolute. Second-place Napoli hosts bottom club Hellas Verona Sunday. "We're nine points ahead of Napoli, but it's not over yet, we have to continue winning," Pogba said. "We played like a mature team today, we deserved to win. "I wouldn't say we're helped by anyone. We make the difference because we defend and attack all together. People talk a lot, but we just have to continue like this, then we'll see at the end." Milan will play Juventus again this season, in the Italian Cup final. Inter moved to fourth, two points above Fiorentina and five points behind third-place Roma, which occupies the final Champions League qualifying spot. Roma hosts Bologna Monday. Frosinone remained one point from safety after fellow struggler Carpi lost at Chievo Verona 1-0. Genoa won at Sassuolo 1-0 in a match which was delayed for several minutes because of a hailstorm. — Agencies