European champions Real Madrid may still lead La Liga, but an air of crisis has enveloped the club after they were torn apart by local rivals Atletico Madrid in a 4-0 defeat last weekend.
Negative press headlines followed not only due to the manner of the defeat, but the timing of a party held by Cristiano Ronaldo to celebrate his 30th birthday along with some of his teammates just hours after the match.
Ronaldo's form on the field is also of concern for the Madrid hierarchy: the Portuguese has scored just three times in six matches since picking up the third Ballon d'Or of his career last month and was also sent off during that run.
Indeed there are fears that the patella tendon injury in his left knee that affected his performances towards the end of last season and most notably at the World Cup could have flared up once more.
Club president Florentino Perez held a meeting with the players and coach Carlo Ancelotti on Monday to tell them in no uncertain terms that their performance at the Vicente Calderon was unbefitting of the 10-time European champions.
However, defeat to Atletico could also prove a turning point in Madrid's season just as it did at the start of the campaign.
After losing two of their first three league games, Madrid travelled to face Depor under a similar cloud only to romp to an 8-2 victory which helped spark a club record 22-game winning run.
Los Blancos are still blighted by injuries with Sami Khedira becoming the latest casalty to join Sergio Ramos, Pepe, James Rodriguez and Luka Modric on the sidelines with a hamstring problem.
However, left-back Marcelo will return from suspension and there could be a debut for Brazilian midfielder Lucas Silva, who joined from Cruzeiro last month.
Just as Real Madrid have faltered, Barcelona have hit their best form of the season so far with 10 consecutive wins to move to within a point of their eternal rivals at the top of the table and 90 minutes of reaching the Copa del Rey final.
The Catalans took their tally to 37 goals in that run with a 3-1 win over Villarreal in the first leg of their Copa del Rey semi-final on Wednesday and will confident of more goals when Levante visit the Camp Nou on Sunday.
Barca won the corresponding fixture 7-0 on the opening day of last season and also stuck five past Levante when they met earlier in the season.
Atletico have had a week off to bask in their derby glory, but will need to keep their winning streak in the league going to maintain their title defence when they travel to Celta Vigo on Sunday.
Spanish international Koke will be sidelined for three weeks with a hamstring injury, but Diego Godin is set to play with a protective mask after breaking his nose early in the derby last weekend.
Elsewhere, Valencia, Sevilla and Villarreal will be confident of picking up three points in their battle for fourth place against the struggling Cordoba, Getafe and Rayo Vallecano respectively.
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