GM Magnus Carlsen only needed a draw to clinch the first Sinquefield Cup and the winner's $70,000 payday. He was offered one, and declined.
Carlsen eventually won against GM Levon Aronian, securing the world number one a plus three score and grabbing the cup by a full point.
"When I finally had the better position, I wanted to use it," he explained of his decision to keep playing on his 38th move. Prior to his opponent's offer, Aronian had Carlsen's pieces in a knot. They began to unravel, and Carlsen sensed the initiative was finally his. He did not see much risk in going for glory.
American GMs Hikaru Nakamura and Gata Kamsky had drawn earlier, so Carlsen knew that a draw or win ensured tournament victory. Had Aronian found a way to convert his earlier advantage, the Armenian grandmaster would have forced a three-way playoff.
He wanted nothing more than to create that chaos. "I had a big advantage and then I played like an idiot," a despondent Aronian said. "I played all the wrong ideas. I felt like I had to win immediately."
Carlsen guessed that Black missed the strength of White's 31st move, and Aronian confirmed that he had. "I just blundered Ne1 and I started playing ridiculous moves," Aronian said. "Losing that position is embarassing."
Nakamura's help from Aronian never came, but he was not afforded the luxury of focusing on the other game. "I would have liked to have paid attention [to Carlsen-Aronian], but considering how quickly my game got out of hand, I didn't really have a chance," Nakamura said.
He tried everything to complicate the position as Black, and although he opened lines everywhere, Nakamura was not significantly better at any point.
Overall, the top American player was pleased with his result. "Any time you pick up rating points, generally it's a good result overall," he said.
Carlsen's $70,000 payday will be his last tournament winnings before the World Championship Match with GM Viswanathan Anand in November. "I don't have too many worries," he said about his study plans.
He also moved his rating north to 2870 - two points from his record high. Nakamura wins $50,000 for second place and is currently fifth on the live rating list. Aronian takes home $30,000 for third and Kamsky $20,000 for fourth.
Club founder and tournament sponsor Rex Sinquefield thanked the players at the closing ceremony.
The host Chess Club and Scholastic Center of Saint Louis also announced its intention of hosting the second edition of the Sinquefield Cup next year. Carlsen said that he wants to return if his schedule permits.
After being overrun with autograph requests (in what has become a daily routine), Carlsen had finished his business and took a walk with his father.
"The final margin of victory is a little flattering," Carlsen said.