Unseeded Frenchman Adrian Mannarino stunned top seed Marin Cilic 6-7 (5-7), 6-4, 6-0 on Saturday to book his place in the Japan Open final against Belgium's David Goffin.
World No. 31 Mannarino, who lost to Yuichi Sugita in the final of the Antalya Open in July in his only previous title match on the ATP Tour this season, dropped the first set in a tiebreak against world No. 5 Cilic but came roaring back in the second to take the match to a decisive third set at Ariake Colosseum.
Mannarino then proceeded to demolish the Wimbledon runner-up to book his place in Sunday's final against world No. 11 Goffin, who outlasted Argentina's Diego Schwartzman 7-6 (7-3), 7-6 (8-6) in the day's first semifinal.