Henin, Myskina and Kvitova are the only significant players that JJ never managed to beat. OTOH, she has wins over Serena, Venus, Sharapova, Kim, Hingis, Davenport, Pierce, Kuznetsova, Mauresmo, Azarenka, Ivanovic, Li, Stosur, Schiavone, Woz, Safina, Dementieva etc. I believe that this stat is more significant than her h2h against Chakvetadze, with all due respect.
About her wins over The Sisters. Jelena was one of the few players with a brain and gameplan against them, she was playing to win, while today's top players are shitting their pants, while they're praying to win 3 games against Serena.