Twelfth seed Mary Pierce rallied to beat Russian sixth seed Elena Dementieva 3-6, 6-2, 6-1 on Friday to become the first Frenchwoman to reach the U.S. Open final.

Dementieva, runner-up last year, ripped through the first set, but after a 12-minute injury timeout Pierce lifted her game to clinch victory and set up a final against Russian top seed Maria Sharapova [Images] or Belgian fourth seed Kim Clijsters [Images].

"It's pretty simple," Pierce explained with regard to her comeback.

"Today, after I lost the first set, I just kept thinking about a friend of mine back at home, Pat, who's sick. She just gave me the power to play today.

"I can't believe it. This is amazing. This is so good. The fans really helped me today."

Smashing winners on both sides, Dementieva began superbly and her serve, which had yielded 62 double faults on her way to the semi-finals, held up well as she won the first set thanks to two breaks of serve.

Pierce, the runner-up at the French Open in June, then had two back-to-back injury timeouts, lasting 12 minutes, reportedly for thigh and back injuries.

The break clearly affected Dementieva as Pierce lifted her game to level the match.

A rattled Dementieva began to make more errors in the third set and the 30-year-old Pierce broke the Russian twice, clinching victory on her first match point to reach the final.

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