A grandmaster from Minnetonka began his bid for the U.S. Chess Championship on Wednesday with a victory in the first round, converting what appeared to be a dead draw into an easily won position.

Wesley So, a 21-year-old Filipino who moved to Minnetonka last fall as he launched his professional chess career, is one of the favorites in the 12-player tournament that will crown the national champion.

In the opening round at the Chess Club and Scholastic Center of St. Louis, he defeated Daniel Naroditsky, a 19-year-old grandmaster from California.

The game was marred by errors by both players, but the biggest was committed by Naroditsky 32 moves into the game at a point where neither player had an advantage.

"I got nervous … and managed to botch it up," Naroditsky said in a postgame interview with commentator Maurice Ashley. "It's ridiculous the way I played in the endgame."

The irony in that statement will jump out at subscribers to Chess Life magazine, for which Naroditsky writes an instructional column on how to play the endgame.

So, the No. 2 seed in the tournament and the eighth-ranked player in the world, also cited errors on his part. He said he completely overlooked a strong reply by his opponent on one move, and added that he was "distracted by some factors," including feeling chilly in the playing hall. He said he also puzzled over the disappearance from the hall of his biggest fan -- the Minnetonka woman who, along with her family, has taken So in like a son when he quit college last year to focus on chess.

Lotis Key usually watches So's game in person, he explained, but she had stepped out to talk with a woman who, along with her husband, are the benefactors of the beautifully appointed club that has become the chess mecca of the U.S.

"Next time if she disappears I know here she is," So said, laughing

The tournament to decide the national champion takes place over 12 days — April 1 to April 12 — with one game per day and a rest day on April 6.

So's two chief rivals in the field are Hikaru Nakamura, who was born in Japan but raised in the U.S., and Russian-born Gata Kamsky.

Nakamura, 27, enters the tournament in peak form, recently jumping from a world No. 10 ranking to No. 3, leapfrogging So. Nakamura has the advantage of having played in more high-stakes tournaments than So, including winning the U.S. championship three times. Nakamura also won his first-round game on Wednesday.

Kamsky is a five-time U.S. champ, including a 19-year gap between his first and second titles (1991 and 2010). He also had an eight-year hiatus from chess after he lost a match for the world championship in 1996. At age 40, he carries a wealth of experience, but he is more likely on the downside of his career, even though he was the surprise winner of the U.S. championship last year. His game on Wednesday ended in a draw.