Kei Nishikori advanced to the quarterfinals of the Barcelona Open with a straight-sets victory over Santiago Giraldo on Thursday.

Nishikori, the top seed and defending champion at the clay court event, broke the 31st-ranked Colombian five times en route to a 6-2, 6-1 third-round victory. It was Nishikori's fifth straight victory over Giraldo, whom he last faced here in the finals a year ago.

"It felt strange to play last year's final opponent in the third round," Nishikori said. "It was a tougher match than the score would indicate. Because I played well at critical times, I'm pretty happy."

Next up for the world No. 5 is Roberto Bautista Agut of Spain. Bautista Agut, the seventh seed, defeated Uruguay's Pablo Cuevas 7-6 (7-5), 6-2. It will be Nishikori's second match against Bautista Agut, whom he beat here last year in three sets.