"It definitely felt good to win again," adds the 19-year-old Cherokee Regional High grad.
Pretty much all I know about this game, trading card, and animation franchise is the signature character Pikachu, a sort of smiley cat-rat with high-voltage electrical powers.
But having never met - much less been - the world champion of anything, I'm eager to learn more about what I thought was a '90s fad gone the way of Pogs.
Silly me. Pokémon (slang for "pocket monster," and pronounced poh-KEY-mun) is mega, maybe even meta. More so all the time.
"It's the second-biggest video-game series, after Mario," says J.C. Smith, director of consumer marketing at Pokémon Co. International in Seattle.
Created in Japan in 1996 and introduced in the United States two years later, Pokémon features 640 characters and 30 games, the latest of which sold 11.5 million copies worldwide in its first six months of release.
Players select teams of Pokémon they hope will defeat the powers of other teams' Pokémon, a word that's singular as well as plural. Combatants can play online or face-to-face using Nintendo devices.
Along with the endless iterations and expanding population of Pokémon, the shrewdly marketed game hooks participants by offering secrets, "special attacks," and strategies.
"People think it looks like a kid's game," says Justin Silverman, 27, a freelance film producer from Maple Shade who has played Pokémon since the late 1990s. "But it's like playing poker while playing Stratego."
As Smith notes, "chess is a good comparison. Except Pokémon is more complex."
The fan base grows because "by the time it's no longer cool for some kids, there's a whole new set," says Silverman. And the non-gory game with the colorful, cartoony characters has a "nostalgic" appeal for older players, he adds.
For Rizzo, who started about age 6, Pokémon "brings back memories from my childhood."
He outgrew the game, but in high school he was drawn back in by new features. The competitions, which began as a United States vs. Japan "showdown" in 2008, also piqued his interest.
"To win, you have to have dedication, and definitely have to do a lot of hard work," says Rizzo.
He spent two or three hours a day playing online matches with other top-tier players in the month leading up to San Diego.
While deep knowledge of the strengths, weaknesses, and other characteristics of hundreds of Pokémon characters is essential, persistence is important, too.
"It's mental," Rizzo says. "You can't give up on yourself even if you lose."
Winning two successive titles was a heady experience. Official videos and photos capture the celebratory, even giddy, atmosphere of the final day.
But wearing the crown (actually, he got a trophy) hasn't gone to his head.
"A lot of people recognize me when I go to tournaments," Rizzo says. "But I haven't gotten recognized walking around campus or around town," he says. "It's still just a video game."
One with major bennies at the highest level, including a scholarship worth $7,500 - and the experience of playing a game you love in front of an audience of people who love it, too.
"I won a free trip to next year's world championship tournament in Hawaii," Rizzo says. "So I'll definitely be competing."
Contact staff writer Kevin Riordan at 856-779-3845, email@example.com, or @inqkriordan on Twitter. Read the metro columnists' blog, "Blinq," at http://www.philly.com/blinq.