head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, and it is a single point.

Execution · Competitive PvP
Stick execution and reading human opponents within a meta-driven system.

Execution · Grand Arena
A football sim testing stick execution, play-call reads, and playbook optimisation against opponents.
FIFA 18 leans Execution (Competitive PvP); NFL 2K1 leans Execution (Grand Arena).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
FIFA 18
Perfect stick skill and timing dominate dribbles and finishing
NFL 2K1
Precise stick control on passes and jukes matters
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
FIFA 18
Human opponents bait, switch tactics and counter your habits
NFL 2K1
Reading a human opponent's play-calls is central
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
FIFA 18
Bounce physics and pack luck add measured chaos
NFL 2K1
Fumbles and catch outcomes add measured chaos
NFL 2K1 leans a little harder on optimization, though the gap is small.
FIFA 18
Formation, squad chemistry and meta mechanics reward study
NFL 2K1
Playbook knowledge and matchup exploitation reward study
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.