Spain signalled a warning to their UEFA EURO 2012 rivals with a slick display of attacking football that produced a second successive friendly win, South Koreathis time the victims as La Roja stepped up their pre-tournament preparations at Stade de Suisse in Berne.
Fresh from lifting the UEFA Champions League trophy with Chelsea FC, Fernando Torres returned to open the scoring with his first international goal in almost a year. Korea's Kim Do-Heon struck a smart equaliser but Vicente del Bosque's side responded after the restart with Xabi Alonso's penalty before Santi Cazorla and Álvaro Negredo sealed a comfortable win for a side still shorn of the FC Barcelona and Athletic Club players who featured in the recent Copa del Rey final.
Boasting seven changes to the side that started the 2-0 friendly victory against Serbia on Saturday, Spain began the encounter on the front foot with Torres deflecting a Cazorla snapshot wide before Alonso drew a flying save from goalkeeper Kim Jin-Hyeon.
Torres and Chelsea club-mate Juan Mata were making their first appearances since their UEFA Champions League triumph eleven days ago and the former marked an energetic display with the game's opening goal after 11 minutes, cleverly glancing Beñat Etxebarría's centre into the top corner.
La Roja continued to seek openings as the half progressed, however, they were stunned by Kim, who rifled past Pepe Reina from the edge of the area. Mata fired wide when well positioned immediately afterwards but Spain were ahead again seven minutes after the restart with Alonso scoring from the spot after Cho Yong-Hyung handled Nacho Monreal's shot.
It got better for the World and European champions when Cazorla sent a free-kick under the Korean wall for 3-1 while Álvaro Negredo ensured a Spanish win with his sixth international goal eleven minutes from time, the Sevilla FC striker drilling home Roberto Soldado's inviting diagonal pass into the box.
Spain next face China in Seville on 3 June before opening their EURO title defence against Italy in Gdansk a week later.