On the eve of the U.S. Tennis Open, world's No. 1 player Serena Williams said what everyone else believes about her game.

Newsday.com reported by the intensity that Williams has when she's on her game that makes her nearly impossible to defeat. Newsday cited Williams' menacing presence as a reason for her psychological advantage.

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And that advantage stems from a mindset that, when Williams has her self-confidence, makes her just about invincible.

"I haven't lost many matches where the player was playing unbelievably well," she said, according to Newsday. "Usually, when I lose, it's because I'm playing unbelievably bad."

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It's an attitude that has helped Williams win 17 Grand Slams, 10 more than the next active player - sister Venus, and 12 more than Maria Sharapova.

But Serena hasn't had that attitude in 2014, at least in the Grand Slam events. She has not advanced past the fourth round in any of the first three slams.

She also created a huge stir with the troubling video of her behavior in a doubles match with Venus, in which she had problems even bouncing a ball. She could not get her serve over the net before the Williamses forfeited three games into their match.

But Serena's dominance returned in her play at the Western & Southern Open in Cincinnati, less than two months after her bizarre Wimbledon incident.

Now, she has a chance to win her 18th slam, which would tie her with Chris Evert and Martina Navratilova and leave her just four shy behind all-time leader Steffi Graf.

"Steffi was a little that way," Evert said of the attitude 22-time major-tournament champion Steffi Graf has that is similar to that of Serena. "I think it's just a form of intensity and the player getting into a certain frame of mind, totally concentrating. It has nothing to do with the opponent; rather, getting themselves psyched up."

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