JOIN USSpain's Nadal, playing his first tournament since returning from an abdominal injury, dominated a brief but richly entertaining encounter against former world number one Safin, who is retiring at the end of the season.
Elena Dementieva earlier joined the exodus of top women's seeds when she was upset 7-5, 6-3 by Poland's Agnieszka Radwanska in the quarterfinals of the WTA's new "crown jewel" tournament.
Nadal will play Marin Cilic for a place in his first final since May's Madrid Masters on Saturday after the eighth-seeded Croatian beat fourth seed Nikolay Davydenko 6-4, 6-4.
Second seed Novak Djokovic reached the last four by beating Spanish fifth seed Fernando Verdasco 6-3, 1-6, 6-1 to move within one victory of reclaiming the world number three ranking.
Djokovic will have to get past Swede Robin Soderling, who defeated Croatian Ivan Ljubicic 7-6, 6-4. The 12th seed will meet France's Marion Bartoli or Russian Vera Zvonareva in the semifinals.
Nadia Petrova had earlier ended Chinese Peng Shuai's giant-killing run, winning 6-7, 6-3, 6-2 to succeed where Jelena Jankovic and Maria Sharapova failed. Svetlana Kuznetsova, who recorded a 6-3, 6-3 victory over fellow Russian Anastasia Pavlyuchenkova.
Youzhny in semis
Russian Mikhail Youzhny knocked defending champion Tomas Berdych out of the Japan Open with a 6-2, 7-6 victory in Friday's quarterfinals.
Youzhny faces former world number one Lleyton Hewitt in Saturday's semifinals after the Australian pulverised Frenchman Edouard Roger-Vasselin 6-4, 6-0 in the day's first match.
Frenchman Jo-Wilfried Tsonga survived a test to beat Latvia's Ernests Gulbis 4-6, 6-4, 6-3 and advance to the semifinals.