The PyeongChang 2018 silver medallist, who had led after Friday's short program (21 February), once again looked full of confidence as he skated to Dancing On My Own in a performance reminiscent of his skate to win the Japanese Nationals in December.
He was awarded a free skate score of 198.70 for a total of 290.41, which both bettered his existing ISU best scores. However, they will not count as his new best scores as they were not set in an ISU competition.
It sets up what will be a mouth-watering return to full international competition at the World Championships in Montreal in March, after the 22-year-old missed the Four Continents.
Tanaka Keiji (241.18) finished second, with France's Adrien Tesson third (209.42).
Like in his short program, the Japanese looked comfortable on the ice and appeared to be enjoying his skating once more.
Uno opened with two flawless quadruple jumps – a Salchow and a flip.
Although he had to step out of an under-rotated quadruple toe loop – the same jump that was his only mistake in the short program – he followed that with a beautiful triple Axel, which scored 3.04 for execution on the -5/+5 scale.
He looked at one with his music, and was seen smiling and laughing during his skate.
This was not the high-pressure environment of a Championships, but it was indicative of Uno's frame of mind, compared to when he fell multiple times during his free skate at the Internationaux de France earlier this season.
Uno completed his jumping elements with two strong combinations – a quadruple toe loop, double toe loop and a triple Axel, Euler, triple flip – with a triple Salchow in between.
He shared a big hug with coach Lambiel as he came off the ice, and was mobbed by the audience on his way to the kiss and cry.
A secondary storyline in the Hague was the two-man duel for Israel's sole World Championships spot between Alexei Bychenko and Daniel Samohin.
Bychenko, a two-time Olympian, would appear to have the upper hand. He finished sixth with 194 points, compared to Samohin's total of 192.74 which was good for ninth.