Shoma Uno is the Japanese national figure skating champion for a third straight year despite struggling with an apparent right ankle injury.
The 21-year-old took a nearly-14-point lead over Daisuke Takahashi from the short program into the free skate in Osaka.
And, despite failing to land any of his first three elements cleanly, the PyeongChang 2018 silver medallist came through the rest of his program without trouble.
His free skate score of 187.04 was nearly 30 points better than bronze medallist Keiji Tanaka, giving Uno a total of 289.10.
Hobbling in warm-ups
Uno appeared to have a difficult warm-up, grimacing in pain on his landings.
And it appeared to tell in his competitive skate, as he was marked down for his opening quadruple flip, triple Salchow and quadruple Toeloop.
But the Grand Prix Final silver medallist followed up with two strong combinations, including a quad Toeloop-double Toeloop, and was simply too good for anyone else on the day.
Uno was attended to by his trainer after competition, receiving strapping to his right ankle.
He attended the victory ceremony wearing shoes, rather than his skates.
Dream comeback for Takahashi
For 32-year-old Takahashi, it was a first national podium finish since another second place six years ago, when he finished behind the double Olympic champion Yuzuru Hanyu.
With Hanyu out of this year's competition through injury, there was an opportunity for the returning Takahashi to once again threaten the top ranks.
After four years out, the Vancouver 2010 bronze medallist showed he could still mix with the big guns.
He landed a quad Toeloop in warm-ups, but couldn't replicate it in his free skate, managing only an opening triple.
Despite a fall during his performance, a free skate score of 151.10 was enough to give him a total of 239.62 for second place, three points ahead of Tanaka in third.