Rusedski, 31, has been in fine form preparing for Flushing Meadows and is currently ranked 30th in the world.
Henman reached the last four a year ago, and has more ranking points to defend as a result.
"There's a great opportunity for me to become British number one and it could happen very soon," said Rusedski, who last topped the British rankings seven years ago.
Rusedski faces American James Blake in the first round before a potential third-round clash with French Open champion Rafael Nadal, but the British number two remains positive.
"It's a tough first match, but I'm extremely confident about winning it," he told BBC Online.
"A lot will depend on how aggressive I am and how I'm serving. We've only played once before (at Indian Wells in 2000) and I won comfortably, so I've got to be confident."
He added: "In November and December last year I worked very, very hard.
"I've concentrated on being more aggressive and going out harder. "Early on in the year I expected to do a lot better, but kept coming up against guys in the top 10.
"Now the hard work's paid off. I've had a great summer and got into the top 30."
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