MADRID (Reuters) - When Real Madrid forward Cristiano Ronaldo collected his third FIFA Ballon d'Or award last month he was enjoying a run of form that was spectacular even by his standards and the European champions were riding high.
Four weeks later and the Portugal captain is mired in a rare slump, Real have been dumped out of the King's Cup by Atletico Madrid and their lead over Barcelona at the top of La Liga has been cut to a point after Saturday's humiliating 4-0 drubbing at their city neighbors.
Alarm bells are ringing at the world's richest club by income and the sense that Real's season may be coming off the rails was heightened by the storm that blew up this week after Ronaldo threw a lavish 30th birthday party hours after the defeat at the Calderon.
The Madrid club's great rivals Barca, by contrast, are on a nine-match winning streak in all competitions led by club talisman Lionel Messi, who Ronaldo beat into second place in the Ballon d'Or vote.
Argentina captain Messi has scored or assisted 14 La Liga goals in 2015, at least twice as many as any other player, while Ronaldo has netted only four goals since the turn of the year.
He was sent off for kicking a Cordoba player in a La Liga match on Jan. 24 and cut a forlorn figure when he returned for Saturday's derby after a two-match ban.
He had just one effort on goal, his joint fewest in any 90-minute La Liga appearance, as Real attempted fewer shots (four) and faced more shots on target (eight) than in any other game this season in all competitions.
Ronaldo's poor form has prompted more speculation he may be carrying an injury and El Pais newspaper reported he is still suffering with the tendonitis in his left knee that hampered him at the World Cup finals in Brazil.
Spanish media reported Real president Florentino Perez held crisis meetings with coach Carlo Ancelotti and the squad this week.
To be sure, the team has been hampered by injuries to key performers including center backs Sergio Ramos and Pepe and midfielders Luka Modric and James Rodriguez.
Saturday's reverse was their heaviest defeat since they were thrashed 5-0 at Barca in November 2010 and they will need a rapid improvement if they are to defend their European crown this term.
Their next outing is at home to Deportivo La Coruna on Saturday before they play their Champions League last-16, first leg at Schalke 04.
Editing by Justin Palmer