Defending champion Kei Nishikori beat Spain's Pablo Andujar to retain the Barcelona Open title on Sunday.
Japan's Nishikori, 25, won 6-4 6-4 to claim his ninth ATP World Tour title.
"I'm very happy," he said. "It was one of the best tournaments so far this year. I always love playing here."
Earlier Britain's Jamie Murray and Australian partner John Peers lost 3-6 7-6 (6) 9-11 to Croatia's Marin Draganja and Henri Kontinen of Finland in the men's doubles final.
Andujar defeated Fabio Fognini and David Ferrer on his way to the final and immediately broke Nishikori's serve in Sunday's match.
However, Nishikori, ranked fifth in the world, broke straight back and eventually ground out a hard-fought victory.
"I hope I can come back next year," added Nishikori.