The solid baseline play and relentless defense of the world No. 5 were too much for the error-prone Ukrainian, whose low first-serve percentage proved costly against one of the best returners in tennis.
For the match, Dolgopolov put just 43 percent of his first serves in and won just 46 percent of his overall service points.
The Spaniard broke serve five times, twice in the first set and three times in the second.
The only remaining Latin American player in the tournament, Argentina's Juan Monaco, saved two match points in the second-set tiebreaker and then advanced to the quarterfinals with a 1-6, 7-6 (8-6), 1-2, ret. victory when American Mardy Fish was forced to retire with a hamstring injury.
The BNP Paribas Masters is the last of this season's nine ATP World Tour Masters 1000 events, which trail only the four Grand Slams and the year-end championship in terms of ranking points.