head to head
Grand Slam Tennis 2 asks more than Grand Theft Auto V, and the gap is execution.

Execution · Practiced Mastery
Stick-controlled tennis testing swing timing and percentage shot selection.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Grand Slam Tennis 2 leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Grand Slam Tennis 2 leans clearly harder on execution.
Grand Slam Tennis 2
Total Racket Control stick swings demand precise timing
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Slam Tennis 2 leans a little harder on reads, though the gap is small.
Grand Slam Tennis 2
Versus humans, disguising shot placement is genuine prediction
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Slam Tennis 2
Ball physics are nearly deterministic
Grand Theft Auto V
Some mission and lobby randomness.
Grand Slam Tennis 2 leans a little harder on optimization, though the gap is small.
Grand Slam Tennis 2
Shot selection and court positioning follow learnable percentages
Grand Theft Auto V
Heists, money loops, builds learnable.
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.