Former US Open winner Samantha Stosur beat Ukraine's Elina Svitolina on Saturday to reach the Japan Women's Open final as she seeks the first successful title defence of her career.

The top-seeded Australian downed third seed Svitolina 7-6 (8/6), 6-2 in Osaka to set up a final against Kazakhstan's Zarina Diyas.

Stosur, 30, is attempting to win in Osaka for a third time after her triumphs in 2009 and 2013, which have already made her the tournament's most successful player.

Diyas reached Sunday's final by beating Luksika Kumkhum 6-2, 7-5, halting the dream run of the Thai who reached her first WTA semis despite not winning a main draw match since March.

Luksika, 21, also won singles silver and doubles gold at the Asian Games in Incheon, South Korea, which finished last week.