Nadal, seeded No. 3, is seeking a ninth consecutive title at the event but had to tough out a challenge from Grigor Dimitrov before advancing with a 6-2, 2-6, 6-4 win.
Nadal posted three breaks in cruising through the first set but Dimitrov dropped just four points on serve and pulled off a pair of breaks in the second set to even the match. He played Nadal even through the first eight games of the third set before Nadal managed a break point and was able to finish it.
World No. 1 Novak Djokovic had three-set matches in his first two matches of the tournament but stopped Jarkko Nieminen 6-4, 6-3 in his quarterfinal. Nieminen jumped out to a 2-0 lead but Djokovic quickly evened the set and, with the first set tied 4-4, won five straight games for control of the match.
Also Friday, Fabio Fognini upset seventh-seeded Richard Gasquet 7-6 (7-0), 6-2 and sixth-seeded Jo-Wilfried Tsonga opened Friday's schedule with a 2-6, 6-3, 6-4 decision over 13th-seeded Stanislaw Wawrinka.
Saturday's semifinals have Djokovic playing Fognini and Nadal taking on Tsonga. Djokovic is 4-0 lifetime versus Fognini and Nadal has won seven of his 10 matches against Tsonga.