Silva struck twice in the second half to further stretch the 2010 World Cup winners' lead after Barcelona’s Jordi Alba had fired them into the lead in the sixth minute and Alvaro Morata had doubled their advantage midway through the first half.
Veteran midfielder Andres Iniesta rounded off the drubbing with a distance strike in the 73rd although there was some concern on the Spain bench when Isco asked to be substituted after a brutal tackle from Kendall Waston although the Real Madrid midfielder did not appear to be seriously injured.
Spain coach Julen Lopetegui said he was unsure if Isco would travel to Russia for Tuesday's friendly against next year's World Cup hosts.
"Isco has a big knock, it's not serious or important and we'll decide tomorrow if he travels to Russia or not," Lopetegui told a news conference.
"What I'm most pleased about was our attitude and we need to keep it up. Every game will be a different world. We have to believe in the type of team we are and have faith in the things we do well."
Lopetegui picked a near full-strength side for Spain’s first friendly since sealing their place in the 2018 finals with an almost perfect qualifying campaign.
He rested No. 1 goalkeeper David de Gea to hand a debut to Athletic Bilbao’s Kepa Arrizabalaga but played an otherwise familiar side which steamrolled its way through qualifying by winning nine out of 10 games and remaining unbeaten.
A talent-filled midfield four of Silva, Iniesta, Thiago Alcantara and Isco ensured Spain monopolised possession in front of a buoyant, sold out crowd at Malaga’s La Rosaleda stadium, barely giving Costa Rica a look in.
The Central American side, who reached the quarter-finals of the 2014 World Cup and will also be in Russia next June, were missing Real Madrid goalkeeper Keylor Navas and his understudy Danny Carvajal proved to be a poor substitute, offering up little opposition to Spain’s attacking onslaught.
Alba thrashed a Silva cutback beyond Carvajal to get Spain off to the perfect start, while the goalkeeper was at fault for the second goal, spilling a tame cross from Silva at the feet of Morata who gobbled up the rebound from close range.
Costa Rica had only one chance of note before the break and Spain showed no mercy after the interval.
Silva pounced on a mix up in the Costa Rica defence to score six minutes into the second period and four minutes later recovered the ball before slamming it low under the grasp of Carvajal to score again.
Carvajal made a third costly slip of the game in allowing Iniesta's distance shot through his hands, capping another impressive win for Spain, who will be one of the favourites to lift the World Cup next year.
(Reporting by Richard Martin, editing by Pritha Sarkar)
