Shisui

“Fire Style! Great Fireball Technique!” Shisui shouted, and an enormous
ball of flames shot out of his mouth.
Itachi stared at the flames streaking toward him, a smile pulling up his lips
at the corners.
Just like Shisui ...
Itachi was thrilled. He gloated to himself that even among the people of
their clan, only his father and Shisui could release a fireball this massive.
Shisui wouldn’t be able to manage a counterattack in time. His defense was slow, too.

Direct hit. “No way!” Shisui cried out at the unexpected result.
The giant ball of flames ripped Itachi into countless pieces, which
transformed into a myriad of crows that attacked all at once.
Substitution.
The real Itachi was running around behind Shisui.
Before Shisui could sense his aura and whirl around, the smaller boy had a
kunai at his throat.
“So you win, huh,” Shisui said, regretfully.
In the end, they sparred thirty-five times. The result was eleven wins for
Itachi, and twenty-four for Shisui.
“You’re beyond genin level already.” Shisui took a swig of water from his
canteen. “Your chunin exam being put off again this year?”
“Yeah,” Itachi replied, before tilting his own canteen back to pour cool
water into his mouth.

Book of Bright Light Chapter 2 Part 4