The 30-year-old Sharapova, who is unseeded in the tournament that serves as a build-up to the Australian Open, is embarking on her first full season since returning from a 15-month drugs ban in April. The five-time Grand Slam champion won the Tianjin Open in October for her first title since her ban, but said after defeating Diyas 6-3, 6-3 in 89 minutes: "I didn't play my best tennis and there's certainly a lot of things to improve on in the next (match). "The great thing is that I'm through and have another chance to play tomorrow."
The other semi-final is between Irina Begu and fellow Romanian Simona Halep, the reigning world number one. Halep, guaranteed top seeding for this month's Australian Open, blew away Aryna Sabalenka of Belarus 6-2, 6-2.