Elena Rybakina clinched the eighth and last spot at next month's WTA Finals when she beat Victoria Mboko 6-3, 7-6 (7/4) on Friday to reach the Pan Pacific semifinals in Tokyo.
The 2022 Wimbledon champion joins the elite field in Saudi Arabia after a successful run of form that also saw her win the Ningbo Open in China last week.
"It's great to qualify and play some more matches, especially against top players," said Kazakhstan's Rybakina, who will appear at the Finals for a third straight year.
"Last week I was focusing one match at a time and I knew that to qualify it's going to take a long road," said the world No 7.
"In the end everything worked out pretty well."
Rybakina will play sixth seed Linda Noskova of the Czech Republic in the semifinals on Saturday.
The No 2 seed made a fast start by winning the first three games against Canada's 19-year-old Mboko on the way to sealing the first set.
The second was more closely contested with Rybakina saving a set point against the 23rd-ranked Mboko before they went to a tiebreak.
Rybakina sent down five aces during the match and hit 23 winners to Mboko's 17.
"It was a very difficult match, I'm really glad I managed to win in two sets," said the 26-year-old.
"It was very tight games but on the tiebreak I think I served well and also played some good points."
Rybakina was locked in a straight battle for the last WTA Finals spot with Russia's Mirra Andreeva.
Rybakina joins Aryna Sabalenka, Iga Swiatek, Coco Gauff, Amanda Anisimova, Madison Keys, Jessica Pegula and Jasmine Paolini at the November 1-8 season-ending tournament.
"I'll try to do well there at the finals for sure, but I think now I played a lot of matches and I'm a little bit tired," said Rybakina.
"I understand that it's important to manage your body and finish the season healthy."
Paolini secured the seventh spot by reaching the semifinals last week in Ningbo.