Real Madrid dropped points for the first time in LaLiga under Julen Lopetegui, Isco's header salvaging a 1-1 draw at Athletic Bilbao.
Iker Muniain bundled home from close range to give Athletic a first-half lead in a bad-tempered clash at San Mames on Saturday, while Unai Simon impressed in goal for the hosts.
But Toni Kroos sent Gareth Bale clear with an excellent chipped pass and substitute Isco flicked in the Wales winger's cross to level shortly after his second-half introduction.
Madrid pressed for a winner but could not beat Simon a second time, leaving Lopetegui's men two points behind league leaders Barcelona, who maintained their perfect record.
Inaki Williams dragged a 14th-minute shot wide and Markel Susaeta came close with a 20-yard drive before twice being denied by Thibaut Courtois as Athletic made a high-octane start.
Simon saved from Marco Asensio, but Athletic took a merited lead in the 32nd minute.
2 - Isco Alarcon scored after two minutes and 56 seconds of coming versus Athletic – the second fastest goal by a substitute in La Liga this season (Real Sociedad’s Juanmi vs Villarreal, 2 min & 33 sec). Vital. pic.twitter.com/eI4nY0nEem— OptaJose (@OptaJose) September 15, 2018
Susaeta got into the Madrid box and the captain's low cross was turned in from close range by a combination of Williams and Muniain, the latter credited with the goal.
Athletic had a second ruled out for offside when Raul Garcia tucked home a Benat free-kick, with Simon again in action as he dived low to his right to keep out Luka Modric's deflected drive.
Simon was fortunate to get away with a poor parry from Bale's free-kick, but the 21-year-old brilliantly made amends to keep out Sergio Ramos on the rebound.
Lopetegui brought on Isco and the Spain star struck the equaliser within three minutes, nodding in unmarked to give Bale's excellent right-footed cross on the run the finish it deserved.
But Simon superbly blocked an Asensio shot in the 68th minute to preserve a point for Athletic, neither side able to find a winner in a frantic finale.
What does it mean: Early advantage to Barcelona
After a chastening loss to city rivals Atletico Madrid in the UEFA Super Cup, Madrid have looked good under new coach Lopetegui. But there was something missing on Saturday, perhaps the X factor previously provided by talisman Cristiano Ronaldo. A two-point gap may seem little to make up at this stage of the season, but defending champions Barca are in ominous form.
Pat on the back: Simon a star in the making
Athletic received a world-record fee for a goalkeeper when they sold Kepa Arrizabalaga to Chelsea, but they might just have a ready-made replacement. Simon was making only his fourth LaLiga appearance, but performed brilliantly, his combative attitude catching the eye as much as his reflexes.
Boot up the backside: Benzema blunt
After Ronaldo's move to Juventus, it is fair to say Karim Benzema initially stepped up. He had scored four LaLiga goals from just five shots on target this season, but performed poorly at San Mames, offering no focal point for the attack. Captain Ramos did not appear impressed, at one point going up front himself.
It is Champions League action next for Lopetegui's men, who host Roma on Wednesday before welcoming Espanyol to the capital in LaLiga three days later. Athletic head to Real Betis a week on Sunday.