Kei Nishikori stunned big-serving Milos Raonic 7-6 3-6 6-0 with an electrifying display of attacking tennis to become the host country's first Japan Open champion.
It was the eighth seed's second career title after winning in Delray Beach in 2008 and will elevate the 22-year-old from 17th to 15th in the world rankings.
Nishikori took the first set tiebreak 7-5 after a jaw-dropping running backhand pass, clenching his fist to salute the roars of a sellout Tokyo crowd.
Sixth seed Raonic, who shocked title holder and US champion Andy Murray in the semi-finals, took the second set, drilling a bullet serve at Nishikori's body as the cheers of the majority among the 13,000 fans turned to groans.
However, Nishikori stormed back in the decider, ripping another fierce backhand pass down the line to open a 4-0 lead, leaving his Canadian opponent gaping in disbelief.
He delivered the coup de grace moments later, a lofted return forcing Raonic to smash a drive volley into the net after two hours, eight minutes to complete a final set 'bagel'.