Real Madrid's week of misery continued as Carlo Ancelotti's men crashed to their second straight La Liga defeat, while Atletico Madrid and Barcelona took full advantage of the slip-up with wins of their own.
A victory to move past the bitter 4-3 loss to Barcelona in the El Clasico last Sunday was essential, but what followed was another horror defeat, with the excellent Sevilla coming from a goal down to pull off a memorable 2-1 victory, their sixth straight in the La Liga.
Cristiano Ronaldo opened the scoring for Real in the 15th minute via a freekick that he himself had won, but Sevilla equalised soon after via Carlos Bacca. Bacca would then hurt Real Madrid yet again, scoring the winner in the 72nd minute after some wonderful play from their skipper Ivan Rakitic, who is having an outstanding season.
"I don't think we deserved to lose," a disappointed Ancelotti said. "On the one hand we could have because we didn't prepare well for Sevilla's counter-attacks and that is how they scored both goals.
"We took the lead and could have scored more goals. Then they scored two goals in the same way when we needed more balance. The first half was good, with a lot of chances, but we were not clinical enough."
At the Camp Nou, Barcelona enjoyed a comfortable 3-0 win over Celta Vigo, a victory that took them temporarily to the top of the table, but the three points were tempered by an injury to goalkeeper Victor Valdes, which rules him out of the season, and most probably the World Cup as well.
Valdes injured himself while saving a freekick from Fabian Orellana midway through the first half, and could not hold back his tears as he left the pitch on a stretcher. Barcelona confirmed the 32-year-old Spanish international had torn his ACL and is now a major doubt for the World Cup in Brazil in the summer.
"It's a very serious injury on a personal level and also for the whole team," teammate Jordi Alba was quoted as saying by the club's official website. "His absence will be significant. We've shared a lot of time together and it's always a shame when a team-mate picks up an injury, even more so when it's Victor Valdes."
Barcelona coasted to victory via goals from Neymar, a brace, and Lionel Messi. "I'm happy that we won," Neymar said. "I'm very happy for the two goals and that we won the other day in the Bernabeu [against Real Madrid].
"The victory is bittersweet because of Valdes' injury."
Atletico Madrid pulled a point clear at the top of the table courtesy a 1-0 win over Granada, with their premier striker Diego Costa scoring the winner. Barcelona are a point behind Atletico on 72, with Real Madrid now two adrift of their bitter rivals, and three behind their neighbours.
"Each match becomes long, hard and difficult," Atletico Madrid manager Diego Simeone said. "The guys are making an incredible and marvellous effort. The season is enormous but it will be valued by how it ends.
"With eight games to go, the advantage is for those who have more resources. We depend on ourselves until the end of the season."
Results: Wednesday: Barcelona 3-0 Celta Vigo; Rayo Vallecano 1-0 Osasuna; Atletico Madrid 1-0 Granada; Sevilla 2-1 Real Madrid. Tuesday: Malaga 1-2 Espanyol; Elche 0-0 Athletic Bilbao.