I wouldn't call it a mind game.
Rather, I would call it a strategy game.
If you watch her wizardly carefully you'll see her full arsenal of tactics which include
plenty of off-pace shots (which opponents often over-hit), crazy angles, low net clearance shots,
moon balls, often waiting to hit the ball until the very last moment, poaching expert etc. etc.
And of course her nerves of steel also come in handy.