British number one Dan Evans missed out on the Madrid Open quarter-finals after losing to German fifth seed Alexander Zverev in the last 16.
Evans, 30, paid the price for a one-sided first set, before being edged out of the second set tie-break.
Nadal comfortably reached his 15th Madrid quarter-final with a 6-3 6-3 win over world number 76 Alexei Popyrin.
Facing the 21-year-old Australian for the first time, Nadal won four of his six break points as he moved closer to a record-extending sixth title in the Spanish capital.
Austria's Dominic Thiem, Madrid finalist in 2017 and 2018, also reached the quarter-finals after beating Australia's Alex de Minaur 7-6 (9-7) 6-4.