For Arvind Mahankali, the third, or, as he would say, t-h-i-r-d, time proved the charm.

The 13-year-old from Bayside Hills, N.Y., won the 2013 Scripps National Spelling Bee Thursday night after correctly spelling "knaidel," the German-derived, Yiddish word for dumpling.

Click HERE to see the expressive faces of the Scripps National Spelling Bee contestants.

"At that time it didn't register that I'd won," Arvind said today on " Good Morning America," explaining why he kept a straight face as confetti fell and his family rushed the stage.

"I was actually ecstatic to have the championship," he said.

Arvind outwitted 11 other finalists and outlasted nearly 2 ½ hours of tense competition in the nationally televised bee, in which he placed third the past two years. Both times Arvind was eliminated on German-derived words, but this year he came prepared and knew he had the title in his grasp when he heard the word "knaidel."

Click HERE for a full recap of the 2013 Scripps National Spelling Bee.

"I had studied 'knaidel' previously," he said on "GMA."

In his third and final attempt at the championship, Arvind, an eighth grader at Nathaniel Hawthorne Middle School, also did some more unlikely prep for the spelling bee, moving from the classroom to the gym.

"I just lifted a couple of weights, you know, so just when the time comes I'd be prepared," Arvind said, knowing he would have to lift the giant gold trophy over his head, as the 85 Scripps National Spelling Bee champs before him have done.

Along with the trophy, Arvind, an aspiring physicist, also won $30,000 cash and a $2,500 savings bond.

Pranav Sivakumar, a 13-year-old from Tower Lakes, Ill., who was tripped up by "cyanophycean," finished second in this year's bee. Sriram Hathwar, 13, of Painted Post, N.Y., placed third.