Serena Williams might be the greatest tennis player of all time, but she came up short in her quest for a Grand Slam. In a stunning match, she lost to Italian Roberta Vinci during the U.S. Open semifinals.

Vinci was unseeded and reached the first Grand Slam semifinal of her career, notes The New York Times. While she dropped the first set, Vinci beat Williams 2-6, 6-4, 6-4.

“This is the best moment of my life,” Vinci said after the match.

She later told the crowd, “For the American people, for Serena, for the Grand Slam and everything. But today is my day. Sorry, guys.”

Vinci’s win sets up an all-Italian final. Flavia Pennetta defeated Simona Halep earlier today, reports ESPN.

Williams was hoping to become the first woman to win the four majors in one season since Steffi Graf did it in 1988. However, Williams did win the U.S. Open last year and, by winning Wimbledon in July, she completed a Wimbledon slam. Still, winning a calendar-year Grand Slam would have been nice.

Pennetta and Vinci have won Grand Slam doubles titles, but this will be the first shot at singles titles for both of them.

image courtesy of INFphoto.com