Jankovic at her dramatic best will lead, throw the lead away, spot you a massive lead in the third set, decide to come back with some blazing retrieving and backhands, almost comeback, and then hand you the win, possibly with back to back double faults or netted forehands. You have no agency in this match. You might start to wonder if you have free will. Perhaps solipsism is true after all - is it Jankovic's world and you're simply allowed to live exist in it? It's basically existential waterboarding.
The belief that man is an irresolute creature pulled this way and that by two forces of equal strength, alternately winning and losing the battle for his soul; the conviction that human life is nothing more than an uncertain struggle between heaven and hell; the faith in two opposed entities, Satan and Christ - all this was bound to engender those internal discords in which the mind, excited by the incessant fighting, stimulated as it were by the constant promises and threats, ends up by giving in and prostitutes itself to whichever of the two combatants has been more obstinate in its pursuit. Life isn't black and white, it's gold.