With the players engaging in hard-hitting baseline rallies, it was Halep that came out on top, breaking serve with a backhand crosscourt to lead 5-4 and then sealing the match with a trademark forehand to complete victory in 77 minutes. Along the way, Halep will become the co-author of a repetition of the record for the second time in history during the season on top of the world rankings will be five players (Angelique Kerber, Serena Williams, Karolina Pliskova, Garbine Muguruza and Simona Halep).
Halep has won 15 WTA and six ITF titles.
She displayed an nearly flawless play in Beijing, where back in 2012 she lost to Sharapova in two sets. That, however, would be all the joy she would get on this day as Halep quickly reasserted her authority, reeling off the next three games to go a set and 3-1 to the good, with Sharapova seemingly unable to find a way back through the defensive-and offensive-prowess of Halep.
Muguruza's world No 1 position is under threat after she bowed out of this tournament in the first round with a virus.More news: TransCanada's Energy East: Not enough oil for that pipeline, analysts say
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Halep will though face a tough test in the final against Garcia, who is chasing successive titles after winning the Wuhan Open last weekend.
An icy Halep served out the match at the end of a solid game on her own terms, converting the first match point she had.
"It was the toughest year but also the best year", said Halep.
In the semi-finals, she'll play ninth-seeded Ostapenko.
French Open champion Jelena Ostapenko of Latvia qualified for the season-ending WTA Finals in Singapore with a 6-3 7-5 win over Australia's Samantha Stosur in round two. A solid first set won by 6-2 put the second seed in front.