BEIJING, China - In a rematch of the French Open final, Romania's Simona Halep ousted Jelena Ostapenko in the semifinals of the China Open, 6-2, 6-4, and made history in the process. 

With the victory, Halep will become the 25th player in WTA history - and first from Romania - to rise to World No.1 when the new rankings are released on Monday. 

She will contest her fifth final of the season on Sunday against the winner of the second semifinal match between No.12 Petra Kvitova and Caroline Garcia.

Read more: Halep makes history, becomes 25th WTA World No.1

WTA CEO Steve Simon and President Micky Lawler were on hand for an on-court ceremony after the match to honor Halep as the new World No.1. 

"It's very emotional, I think it's the first time I cried on court," Halep said on-court after the match. "It's amazing that I could do this. My team, everyone at watching, and I want to thank everyone. It's my special day.

"When I was five points away, I felt that I want it more and more. I try just to not think too much about that, to stop thinking, because you feel the pressure when you're thinking too much.

"I will never forget this day or this tournament. I always get great support in China, and I'm waiting for tomorrow - the tournament is not finished."

With 14 winners and 10 unforced errors, Halep put on a tidy performance in one hour, 15 minutes, in which she hardly trailed.

The result flipped the script of June's French Open final, in which Halep led Ostapenko by a set and a break, with points for a double break in the second set, only to see the Latvian come all the way back and stun the tennis world for her first Grand Slam title. 

"I didn't think too much that I am again in the same position. In French Open I was a set and 3-0, so here was a little bit different. Still, she played really well those games, those next games," Halep reflected. "I was not worried. I just tried to stay focused, to not going back, to not going too farther from the baseline. I tried just to block all the balls and to hit the balls.

"The serve was maybe the best thing today during the whole match. I think mentally I was different, and that's why I could win the match."

Halep broke Ostapenko's serve four times in the match and served five aces of her own to clinch victory, beginning the match with a love break and sealing it with a love hold to rise to the WTA summit.

From Evert to Halep: All 25 WTA World No.1s

Ostapenko's blistering groundstrokes struggled to find their mark for much of the semifinal encounter, as the Romanian's stellar defense pressed the Latvian into unforced errors, 32 in all to go along with 27 winners.

"Of course, it's a great thing. Many others did it, and I'm one of them. I'm really happy about that, but I'm in the middle of my career, so I have many years ahead. I just want to stay the same, focused, and do my job."

- Simona Halep on reaching World No.1

Halep saved the lone break point she faced in the opening set in the sixth game, before sealing herself some insurance with a second break in the longest game of the match and powering to a one-set lead behind her first love hold.

Ostapenko battled hard for the duration of the second set, keeping in front with a series of successive holds, and battling back immediately when Halep earned the first break of the set in the fifth game. 

However, the Latvian's love hold to lead 4-3 proved to be the last game she won in the match, as the Romanian upped the tempo and pressure to win the last three games of the match to seal her historic achievement and a place in the final.

"Tomorrow morning before my practice, like I did every day here, I will talk to my team about the tactic and about how I have to play," Halep said of Sunday's championship. "I know both of them. I know that they are very strong opponents. They hit very strong the balls and they stay close to the lines.

"I have to just think about the match against [Maria] Sharapova, today against Ostapenko, because they play similar. I just want to, again, go there and take the match."