Russian Korzhanenko, 30, took the lead in the first round with 20.41, improved to 20.70 in the second and then launched her winning throw in the third.
Cuban Yumiledi Cumba was second and German Nadine Kleinert was third in the first athletics competition staged at the site of the ancient Games since AD 393.
Korzhanenko was awarded the 1999 world indoor title when Ukrainian Vita Pavlysh was disqualified for doping but then lost the title herself when she also tested positive.
