SHENZHEN, China, Jan. 4 (Xinhua) -- Former world No. 1 Maria Sharapova and world No. 1 Simona Halep both defeat their rivals by straight sets to reach the semifinals of WTA Shenzhen Open here on Thursday.

The 30-year old Russian dispatched Zarina Diyas from Kazakhstan, 6-3, 6-3. Sharapova hit 24 winners and five aces to clinch victory in one and a half hour.

"I feel like I'm having a nice little tour of China, it's my fourth Chinese city in a few months," Sharapova said, who won her 36th title in Tianjin Open last October and keeps a 8-match winning streak in China.

"It's obviously been a great welcome here. It took many years for me to play this event but I'm really glad that I did." she added.

Sharapova will play defending champion and No. 6 seed Katerina Siniakova in the semifinal, who beat Kristyna Pliskova 6-2, 6-2.

World No. 1 Halep eased past Belarusian Aryna Sabalenka, 6-2, 6-2, in just 57 minutes. The World No. 1 will face No. 4 seed her countrywoman Irina-Camelia Begu in the semifinals, who edged past Timea Babos, 7-5, 7-5.