WTA Rising Stars Invitational champion Naomi Osaka pulled off a big upset by beating Nao Hibino in an all-Japanese semi-final at the Hua Hin Championships to set up a showdown with Yaroslava Shvedova.
Hibino was expected to see off a compatriot ranked 125 places below her, but the third seed was beaten 4-6 6-3 6-1 in the last four of the WTA 125k series event in Thailand on Saturday.
Osaka, who won the Rising Stars title in Singapore last month just a week after turning 18, sent down 17 aces and grasped four of the eight break-point opportunities she earned.
World number 203 Osaka lost just the one service game in an impressive display and will need to maintain those high standards when she takes on fourth seed Shvedova.
Kazakhstani Shvedova also had to come from a set down to reach the final, winning 6-7 (4-7) 7-6 (7-4) 6-4 against Wang Qiang.
Shvedova stayed in contention to win her first title of the year, but was given a major test by the unseeded Chinese in a contest which lasted two hours and 42 minutes.