13-year-old Ansun Sujoe and 14-year-old Sriram Hathwar hoisted the gold cup after they saw off 10 other finalists and then spelled their way through the demanding final list of 25 words.
Hathwar would have been the champion after correctly spelling "stichomythia", meaning a dialogue of altercation in Greek drama.
But then Sujoe came through with the final word, feuilleton, a French-derived noun for a newspaper supplement or soap opera.
They'll each take home a golden trophy and more than $30,000 in cash and other prizes.