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.