THE biggest-ever US National Spelling Bee ended suddenly as wildcard debutante Karthik Nemmani correctly spelled out koinonia to KO hotly tipped Naysa Modi.

Four-time entrant Naysa, 12, had already vanquished the 14-year-old victor at the county level but her nous left her when she forgot the double “s” in Bewusstseinslage — a state of consciousness or a feeling devoid of sensory components.

Karthik pounced, picking the right letters for haecceitas (“thisness”) in round 17 and koinonia, Christian fellowship or communion, for the final round.

“I didn’t really think I’d be able to do it,” the soft-spoken winner said. “I had confidence that I could do it, but I honestly didn’t realistically think it could happen.”

Karthik wouldn’t have made it to the nationals before this year, when the sponsors introduced the RSVBee programme, giving kids from spelling hotbeds the chance to make it to the big time on a wildcard.

The last three spellers were all from Dallas, which only sponsors two competitors to the Gaylord National Resort in National Harbour, Maryland.

Karthik is from McKinney, Texas — his family moved there specifically so he could go to a school that takes part in bee. Naysa is from Frisco, less than 15 miles to the west, and third-placed Abhijay Kodali lives in Flower Mound, another 40 miles west.

Naysa had dispatched Karthik at the county level and beat Abhijay (who dropped out at the nationals for thinking aalii, a bushy shrub, only has one a) at the regionals.

The field was expanded to 515 competitors — having never topped 300 before — to accommodate the change, while one-quarter of the last 16 were wildcards, who have to pay the $750 entry fee and cover the cost of travel and lodging themselves.

“I don’t care,” said Karthik’s father Krishna Nemmani. “I know his calibre.”

Karthik is the 14th consecutive Indian-American champion, and 19 of the past 23 winners have had Indian heritage. He took home $42,500 in cash and more in other prizes.

Naysa, who does taekwondo and performs stand-up comedy, will have to regroup after a bitter defeat and try again next year. She’ll be in eighth grade, which is the final school year that spellers are eligible. She first competed in the bee aged nine.

Karthik, for his part, took no pleasure in vanquishing a familiar foe.

“I wouldn’t say it was revenge,” he said. “We weren’t against each other. We were against the dictionary.”