"I'm glad that I ended up being the winner of the match," Sharapova said in a courtside interview.
"I didn't play my best tennis and there's certainly a lot of things to improve on in the next. The great thing is that I'm through and have another chance to play tomorrow."
The five-times grand slam champion committed 22 unforced errors in the match but stepped up her game at decisive moments of the contest to get past her spirited rival.
Sharapova's only title in 2017 came at the Tianjin Open, after she came back from a 15-month doping ban, and the world number 59 is aiming for a title-winning start to the year in her first visit to Shenzhen.
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"I feel like I'm having a nice little tour of China. It's my fourth Chinese city in a few months," Sharapova added.
"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."
Sharapova plays Katerina Siniakova next after the defending champion beat fellow Czech Kristyna Pliskova 6-2 6-2.
Earlier, fourth seed Irina-Camelia Begu had to work hard to overcome Timea Babos 7-5 7-5 to set up a semi-final meeting with her compatriot Halep.
(Reporting by Shrivathsa Sridhar in Bengaluru, editing by Pritha Sarkar)
