Spain head coach Julen Lopetegui says the recent success of La Liga's three powerhouse clubs has spawned a positive atmosphere within his World Cup squad.
Atletico Madrid and Real Madrid won the Europa League and Champions League respectively in May, while Barcelona almost went unbeaten in romping to the league title.
The rush of silverware comes as a good omen for Spain with the trio home to 12 of the 23 players bound for Russia.
Lopetegui views the triumphs as a handy boost to morale, but warned the national team must work hard to maintain the trend.
"Barcelona, Atletico Madrid and Real Madrid have won titles. That's good because they're happy," Lopetegui told reporters on Saturday.
"We always say we want our players happy. Now it's our turn to work.
"From now on we don't focus on those facts or situations, but on what we need to give the team for it to be closer to a win in every game."
Manchester United goalkeeper David de Gea is one of the few players in Lopetegui's squad to be based abroad, although he has long been linked with a move to European champions Madrid.
The 27-year-old, who was an unused member of the squad that crashed out in the group stage in 2014, brushed off questions regarding his club future, insisting he is focused only on Spain's opening match against Portugal.
"I'm always calm. The important date is June 15th," De Gea said.
"The World Cup is important, for us to deliver a good performance, for the team to do well and for things to go as well as possible.
"I am happy, very pleased and very focused on the national side."
