Nishikori, the No. 4 seed, defeated Feliciano Lopez 7-6 (7-4), 6-0. After a tight first set in which both players had a pair of breaks, Nishikori won more than three-quarters of the points in the second set, finishing off three of his four break chances. Lopez won just eight points in the set.
No. 3-seeded Milos Raonic, who lost to Nishikori in the Japan Open final last year, also gained a spot in the quarters, taking out Jeremy Chardy 6-4, 6-3 without facing a break point. Raonic had 17 aces and lost a mere seven points in his 10 games serving.
Nishikori takes on Almagro in Friday's quarterfinals. They are in the same half of the draw as No. 1-seed Juan Martin del Potro and Alexandr Dolgopolov. Raonic goes against Lacko in the bottom half of the draw where Ivan Dodig and Jarkko Nieminen make up the other quarterfinal.
2014: The Year in Music [PHOTOS]