Halep lost to Ostapenko in this year's French Open final but gained revenge with a superb display in Beijing that took just 75 minutes.
She will officially end the four-week stand of Spain's Garbine Muguruza at the top of the table on Monday, with just a few weeks left in the regular WTA season.
In the men's draw, world number oneRafael Nadal beat Grigor Dimitrov to set up a tasty final showdown with temperamental Australian Nick Kyrgios, who pulled off a stunning 6-3, 7-5 win over starlet Alexander Zverev.
Despite hitting more winners than her rival, Sharapova committed 39 unforced errors and struggled to contend with the Halep's power and aggression in Beijing.
Halep broke Ostapenko'sserve in the first game at love and expanded the lead to 5-2 with another break in the seventh game beforing serving out the first set.
But Halep steeled herself and reeled off three successive games to become the 25th player in the history of the WTA rankings to sit at top spot.
"It's very emotional, I think it's the first time I cried on court", Halep said on-court after the match.
The 26-year-old is the first Romanian to hold the ranking. "I really want to do better, and I know I have to try to dominate the point or I will run a lot".
That said, with 9 of the Top 10 players entered (only Venus didn't make the trip), Simona Halep was the only Top 8 player to make the semifinals.
Ostapenko made a typically high 33 unforced errors, but her powerful forehand kept her out of trouble against Romanian Cirstea, who is also her doubles partner. In the quarter-finals, she meets the victor between 11th-seeded Agnieszka Radwanska of Poland and Russian Daria Kasatkina.
Chandimal took a little while to get adjusted to the conditions as he scored just one run off the first 23 deliveries he faced. The management will be unwilling to risk him though and would much rather save him for the ODI series .
Officials in Sudan say that since the September 11, 2001, attacks, the Sudanese have been cooperating with USA intelligence. He is wanted by the International Criminal Court on genocide charges for allegedly orchestrating a mass killing in Darfur.
North Korean leader Kim Jong Un inspects the intercontinental ballistic missile Hwasong-14 in this undated photo released by KCNA. Dr Raja added he knew airports in the USA and United Kingdom had the detecting devices for VX.
In the month of March, Khalid Masood killed four people and left more than 50 injured in a similar fashion at Westminster Bridge . A witness said that a number of people were taken away in ambulance, however the extent of their injuries is unclear.
More than 2.3 million undocumented immigrants in California are now officially protected under a new state sanctuary law. But the decision means California could lose millions of dollars in grants from the federal government.
The Sooners moved 72 yards on 11 plays in their second series , scoring on a 15-yard Mayfield to CeeDee Lamb pass. The Sooners bolted out for a 14-0 advantage in the first quarter, but Iowa State refused to be beaten down.
The Danish Prosecutor Jakob Buch-Jepsen told the court that on the hard drive, which, I believe, belongs to Mr. Madsen has also denied amputating her limbs, saying he tried to bury her whole body at sea.
Trump said that all forces that undermine USA national interests must already be destroyed, and that it remains to be done. Sanders said that Trump would announce the new reaction to Iranian moves within the next week.
She had entered the Philippines in September 15, and again on September 25, traveling on her Australian passport, she said. Authorities believe Paddock brought the weapons into the hotel by himself, but they did not provide specifics.
Kane has followed up successive Premier League golden boots with a blistering run of 14 goals in nine games for club and country. Gareth Southgate wants to include Jack Wilshere in his World Cup squad if he proves his form and fitness with Arsenal .
Black Stars draw against Cranes in World Cup qualifier
The Ghana Football Association (GFA) has asked FIFA to consider replaying the match and also sanction the match officials. However, a number of missed chances from both sides and poor officiating meant neither side could find a breakthrough.