With 104.63 points, Uno has a small margin over Malinin (100.38 points), while Korea's Cha Jun-hwan (99.64 points) completes the provisional podium.
The 25-year-old, who plays on John Mayer's "Gravity", did not seem bothered after a fall the day before in training that had caused him pain in his right ankle.
Coming off the ice, he tightened the point and wore a big smile after putting on his best performance of the season on a short program.
The American teenager, who proclaimed himself "QuadGod" after becoming in September the first to pass a quadruple axel in competition, has lived up to the turmoil he creates around him by improving his best total.
To the tune of Garou's "I Put A Spell On You" and all dressed in black, he did not place his signature jump this time, probably reserving it for the free program scheduled for Saturday.
Olympic champion Nathan Chen is not present in Japan, nor is the Russian contingent, which is still suspended due to their country's invasion of Ukraine.
© 2023 AFP