Uncork a bottle of your finest Barolo or pop open your most bubbly prosecco. On Saturday, an Italian woman is going to win the U.S. Open title.

After an extraordinary pair of semifinals Friday at Arthur Ashe Stadium, Roberta Vinci and Flavia Pennetta will meet there again on Saturday to contest the last Grand Slam championship of the year.

After Pennetta beat world No. 2 Simona Halep in the first semifinal, Vinci stunned world No. 1 Serena Williams.

What odds could you have gotten that the 33-year-old Pennetta would meet the 32-year-old Vinci in the final? Neither had been to a Grand Slam final; Vinci hadn't been to a semifinal until Friday. Pennetta is ranked 26th and Vinci 43rd. And think about this: Whoever wins Saturday will win her first tournament of the year.

This is the first time two Italians have faced each other in a Grand Slam final.

Two Italians reached Slam finals before. Francesca Schiavone, the only Italian to win a Slam, took the 2010 French Open and lost in the final in 2011. Sara Errani lost in the 2012 French Open final.

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"It's amazing because 20 days ago, my physio asked me if I . . . think I can win a Grand Slam or be in the final of a Grand Slam, and I say no," Pennetta said. "For a lot of reasons, I think my answer was no, but like I always say, you never know."

Vinci was equally surprised at her fate.

"I'm 32, almost at the end of my career, and then I make the first U.S. Open final in a Grand Slam. I don't expect this."

Having failed to come close to beating Williams in four previous matches, Vinci didn't like her chances.

"Maybe if you told me 'tomorrow you can win against Serena,' I say, 'Come on!' '' Vinci said. "[On Thursday] I called my travel agency to say, 'OK, book me a flight [on Saturday] because, you know . . . "Now it will be Sunday at the earliest before the two head back to Italy. Pennetta holds a 5-4 career advantage over Vinci, who is better known as a doubles player who won five Grand Slam titles with Errani.