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

Execution · Competitive PvP
Tests shot timing and play-calling prediction against human defenders.

Execution · Competitive PvP
Execution on the ball plus constant prediction of the other player's shape.
NBA 2K15 leans Execution (Competitive PvP); Pro Evolution Soccer 2009 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.
NBA 2K15
Shot-stick timing and dribble moves demand practiced hands
Pro Evolution Soccer 2009
Close control and finishing windows demand stick precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
NBA 2K15
Versus humans, baiting defenders and calling counters drives possessions
Pro Evolution Soccer 2009
Online and couch opponents adjust tactics against you
NBA 2K15 leans a little harder on variance, though the gap is small.
NBA 2K15
Shot RNG and loose balls swing close games
Pro Evolution Soccer 2009
Ricochets and keeper parries add small randomness
NBA 2K15 leans a little harder on optimization, though the gap is small.
NBA 2K15
Playbooks, matchups and roster management reward system study
Pro Evolution Soccer 2009
Squad setup and tactical sliders reward preparation
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.