Unseeded Slovakian Dominika Cibulková beat crowd favourite Nao Hibino to set up a clash with recently-crowned US Open champion Naomi Osaka of Japan at the Pan Pacific Open in Tokyo.
The game was a thriller, taking Cibulková two hours and 13 minutes to beat the Japanese player, who was cheered on by the home support, 6-1, 5-7, 6-3 at the Arena Tachikawa Tachihi.
Osaka received a bye into the second round, meaning her game against Cibulková will be her first on home soil since beating Serena Williams to win the US Open.
In other first round fixtures, the former world number one Garbiñe Muguruza of Spain beat 2015 runner-up Belinda Bencic of Switzerland 6-2, 6-4, setting up a second round match against Canadian Eugenie Bouchard or American Alison Riske.
"I like to play here," Muguruza said.
"In the past I've done well, so I'm positive this year that I can do well again and go far."
Camila Giorgi of Italy also defeated Misaki Doi fairly quickly, beating the Japanese player 6-2, 6-1.
She will now play Caroline Wozniacki of Denmark on Wednesday (September 19) after the world number two received a bye into the second round.
Last year’s runner up Anastasia Pavlyuchenkova of Russia won her match against Belarusian Aliaksandra Sasnovich 6-3, 6-4, setting up a second round tie with Caroline Garcia of France.
Australian Daria Gavrilova overcame wildcard Kristýna Plíšková of Czech Republic 7-6, 3-6, 7-6 and will now play her twin, Karolína Plíšková.
Estonian Anett Kontaveit secured her place in the second round, defeating French player Kristina Mladenovic 6-3, 7-6.
The first round will be completed tomorrow, with the likes of Bouchard taking on Riske and Gabriela Dabrowski of Canada coming up against Briton Johanna Konta.
The event is a Women's Tennis Association Premier competition.