Real Madrid missed the chance to cut the gap on Barcelona at the top of La Liga as Athletic Bilbao held the champions to a goalless draw at San Mames on Saturday evening.
Karim Benzema struck the post early in a game that Real struggled to stamp their authority on, with Zinedine Zidane's side looking devoid of ideas on a cold night in the Basque Country.
Cristiano Ronaldo came closest to winning it for the visitors when he hit the woodwork with a fine volley midway through the second half, but any hope Real had of taking advantage of Barca's dropped points earlier in the day were dashed when Sergio Ramos was red carded for an elbow in the face of Aritz Aduriz.
The result leaves Real in fourth place, still trailing Barca by eight points, whilst Athletic move up to 15th.
Real had briefly shown some attacking industry early on and nearly broke the deadlock after 10 minutes, Ronaldo bursting forward from deep and playing in Isco whose whipped cross was chested down and rattled against the post by Karim Benzema.
The France striker caused chaos in his own defence 15 minutes later when his sloppy ball across the Real penalty arrived at the feet of the grateful Mikel Rico, but the midfielder was closed down as he looked to make space to shoot.
Inaki Williams had the hosts' best chance of the first half, receiving the ball on the end of a neat one-two from Raul Garcia and striking low across Keylor Navas, only to be denied by a fingertip save from the goalkeeper.
Aduriz had a clear sight of goal for Athletic at the start of the second half, lining up a first-time drive from a driven cut-back which Navas did well to beat away.
Ronaldo was noticeably subdued and has managed only two goals in La Liga this season, but the forward came desperately close to adding to his tally here, cracking a volley off the base of the post from distance as the ball dropped over his shoulder.
It was a rare moment of brilliance from an out-of-sorts Real, and their torrid night was capped when Ramos saw red late on for landing an elbow in the face of Aduriz.
Man of the match - Mikel Rico
The Athletic midfielder was a daunting presence in front of the back for as Real struggled to find the fluency they craved to break the hosts down. He was always the first player in the face of the champions' attacking trio and that none of Ronaldo, Isco or Benzema ever looked settled at San Mames was in no small part down to Rico's industry.
What's next?
Real Madrid face Borussia Dortmund in the Champions League on Wednesday at 7.45pm, whilst Athletic Bilbao play away at Zorya in the Europa League on Thursday at 8.05pm.