head to head
Dragon Ball Z: Budokai Tenkaichi asks more than Boxing, and the gap is optimization.

Execution · Pure Mechanics
A two-minute test of joystick reflexes and simple punch-trading rhythm.

Execution · Competitive PvP
Fast arena combat that tests combo execution and counter prediction against human opponents.
Boxing leans Execution (Pure Mechanics); Dragon Ball Z: Budokai Tenkaichi leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Boxing
Joystick speed and punch timing decide the two-minute bout
Dragon Ball Z: Budokai Tenkaichi
Combo timing, dashes and beam clashes reward fast hands
Dragon Ball Z: Budokai Tenkaichi leans a little harder on reads, though the gap is small.
Boxing
A human second player can be baited and predicted
Dragon Ball Z: Budokai Tenkaichi
Versus humans, predicting teleport counters and ki tactics matters
Dragon Ball Z: Budokai Tenkaichi leans a little harder on variance, though the gap is small.
Boxing
Nothing hidden or random in the ring
Dragon Ball Z: Budokai Tenkaichi
Almost nothing random once movesets are known
Dragon Ball Z: Budokai Tenkaichi leans clearly harder on optimization.
Boxing
Scoring rules are shallow; positioning tricks are quickly learned
Dragon Ball Z: Budokai Tenkaichi
Character matchups and attribute builds are learnable systems
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.