Real Madrid's Spanish record 22-match winning streak ended in a 2-1 La Liga defeat at Valencia on Sunday with Nicolas Otamendi heading in the second-half winner.
Real took the lead after Alvaro Negredo handled a Toni Kroos free kick in the penalty area and Cristiano Ronaldo coolly placed the spot kick into the corner with 14 minutes played.
An Andres Gomes shot deflected off Dani Carvajal and hit a post in first-half stoppage time as Valencia battled back and Antonio Barragan then had a shot deflected in off Pepe in the 52nd before Otamendi nodded home a corner after 65 minutes.
Real, who last dropped points against Atletico Madrid in mid-September, are a point clear of Barcelona at the top of La Liga.
"We have to give credit to Valencia. It's sad that we have dropped three points and our run has come to an end but the league is long," Real defender Sergio Ramos told reporters.
"Before we didn't say that we had it won and in no way are we now going to say we have lost the league.
"Valencia played their way and did very well. They packed players in the middle of the pitch and took the points."
It all looked good for Real early on with their lethal counter-attacking putting them ahead. Gareth Bale was brought down by Lucas Orban and from the resulting free kick, Real won the penalty.
The game, though, became feisty with plenty of chances for both sides and it was Valencia’s greater drive that allowed them to turn the game around in the second half.
It was a poor start to the New Year for Real, who picked up their fourth piece of silverware in 2014 when they won the Club World Cup last month.