Spain cannot let club rivalries infiltrate into the national team if they want to retain the FIFA World Cup, says coach Vicente Del Bosque.
With the top three teams separated by three points in La Liga this season, the title race could go down to the very last weekend when defending champions Barcelona face Atletico Madrid.
The majority of Del Bosque's World Cup squad is expected to be made up of players from Real Madrid, Atletico and Barcelona and he has called for unity once the season has finished.
Head-to-head matches between the sides have been fiercely competitive, but Del Bosque expects all frictions to be forgotten when Spain head to Brazil.
"With good relationships between the players we will be closer to success," the coach is reported as saying in AS.
"There are many great teams that also want to be world champions, so repeating (their 2010 victory) is very complicated."
Spain lifted their first world title in South Africa in 2010 and could become only the third nation to retain the title after Italy (1934 and 1938) and Brazil (1958 and 1962).