Osaka, 12 October 2013 | AAP

Samantha Stosur has advanced to the final of the WTA’s Japan Open with an emphatic win over 18-year-old American Madison Keys.

The Australian thrashed Keys, who was aged just four when Stosur turned professional in 1999, taking only 61 minutes to triumph 6-1 6-2 on Saturday at the Utsubo Tennis Centre in Osaka.

Stosur will face Canadian teenager Eugenie Bouchard, who defeated unseeded Kurumi Nara of Japan in the other semifinal.

Seeded three, Stosur will fancy her chances of claiming her second title of the year after beating world No.1 Victoria Azarenka in the final of the Southern California Open in August.

Her passage to the decider in Osaka was helped by the withdrawal of top seed Jelena Jankovic just before the tournament started and second seed Sabine Lisicki pulled out of her second-round clash against Polona Hercog due to injury.