Henin has yet to drop a set in New York this year

The Belgian, who is trying to add a second US crown to the one she took in 2003, came through 7-6 (7-2) 6-4 in Friday's second semi-final.

Henin is the first player to beat both Venus and Serena Williams in a Grand Slam tournament since 2001.

She will face Svetlana Kuznetsova in the final on Saturday after the Russian beat compatriot Anna Chakvetadze.

"It has been really, really important to me in this tournament to play both of them," said Henin after becoming the second player, after Martina Hingis at the 2001 Australian Open, to beat both Williams sisters at the same Grand Slam.

"It was a great challenge and I did it."

I just feel like I was fighting some circumstances that I couldn't conquer Venus Williams

The first semi-final of the day was disappointing but world number one Henin and Wimbledon champion Williams immediately got the pulses racing.

Henin, in particular, began in superb form, breaking serve at the first opportunity and looking on course for a straightforward set when serving at 5-4 and 40-15.

But Williams has been in great form recently and, spurred on by her home crowd, got back to deuce with two winners and saved another set point before breaking back.

It came down to a tie-break and it was Henin who dominated from the outset, firing a spectacular forehand winner on the first point and moving 4-2 clear with an ace.

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The top seed soon wrapped up the set and broke at the start of the second in a burst of untouchable form.

Williams was not about to lie down and recovered the break in game five before moving 0-40 clear on Henin's next service game.

The American could not convert, however, making three unforced errors as Henin managed to cling on.

Williams called for the trainer at the changeover and it was little surprise that Henin broke in the next game, but still the drama was not over.

I just went with my heart, kept fighting a lot Justine Henin

Henin could not serve out the match as Williams dug deep to find some heavy returns but the American looked tired in the following game, missing with a forehand on match point to put the world number one into the final.

"I just went with my heart, kept fighting a lot," said Henin. "We both played great tennis. I got a bit nervous, but finally I did it and I am so happy.

"I had problems with my breathing in the last few days and the match was really intense but I just tried to focus as hard as I could."

Williams said that the physical problems she encountered in the second set had played a part in her defeat.

"I was just feeling dizzy, a little sick to the stomach, having some energy problems. I'm not really sure what's wrong with me," she said. "But credit to her for playing well."

"I just feel like I was fighting some circumstances that I couldn't conquer. I'm disappointed obviously.