Flavia Pennetta of Italy poses with her Women's US Open Tennis champion trophy at the Top of The Rock in New York, Sept 13, 2015. [Photo/Agencies]

Calling it quits after all-Italian final against childhood friend

For Flavia Pennetta, summing up her shocking US Open triumph was easily described in a single word.

"Perfect."

Pennetta, at 33 the oldest first-time Grand Slam finalist in the Open era, on Saturday became the first Italian to win the US Open women's crown with an efficient 7-6 (4), 6-2 victory over compatriot and childhood friend Roberta Vinci.

Before accepting the trophy and $3.3 million for the win that easily marked the greatest triumph of her career, Pennetta announced her retirement.

"My life is perfect," Pennetta said when asked how she would look back at the championship.

"Perfect. This one was my last US Open match and I couldn't think to finish in a better way."

Two weeks ago, no one could have predicted a final between the 26th-ranked Pennetta, then rated a 150-1 outsider, and the 43rd-ranked Vinci, an even longer shot at 300-1.

But both players refused to be swayed by the odds and fought their way through to the most unlikely title showdown in memory.