Real Madrid head coach Zinedine Zidane was left to rue a wasteful display from Los Blancos as the defending champions dropped two points off the pace in LaLiga.
Madrid were held to a 1-1 draw by Elche on Wednesday, with Fidel's penalty cancelling out Luka Modric's 20th-minute opener.
Modric scored his first header after 26 goals and 364 games in all competitions for Madrid.
LaLiga holders Madrid mustered 14 attempts, managing six on target, with substitute Eden Hazard squandering a chance late on – the Spanish giants have hit the woodwork 18 times across all competitions this season, more than any other club in the top five European leagues.
The draw, combined with Atletico Madrid's earlier win over Getafe, leaves Zidane's side two points behind their city rivals.
Atleti also have two games in hand, but Zidane insisted there will still be plenty of twists in the title race.
"The season is very long, there is a lot to do," Zidane told Movistar. "All teams are going to lose points.
"We have to continue our business, keep fighting, we are going to lose points and that's why we have to continue.
"We come from many good games, with good results, today there was a break but we have to continue.
"We have had chances to kill the game, but that's how it is, when they scored the goal, they went back and it was very difficult.
"Before we had chances to score the second, we didn't and this is football."
Madrid had won five successive LaLiga fixtures heading into Wednesday's fixture, though Zidane does not believe his team showed any complacency or overconfidence.
"I don't think so because we knew what was at stake today," he added.
"They are three important points in a complicated field. But when they tied level it was more complicated. We have also had chances but it has not been possible."