FLUSHING MEADOWS, N.Y., Sept. 11 (UPI) -- Serena Williams had been down a zillion times before. But this time, there was no coming back.
Just two victories away from capturing tennis history, the world women's No. 1 fell in a spectacular upset at the United States Open Tennis Championships Friday -- to an unseeded Italian who had never before played in a major final.
Vinci matched Williams shot-for-shot for exactly two hours -- and held on just long enough to dethrone the defending champion, 2-6, 6-4, 6-4.
Serena seemed to be on cruise control early in the match, taking the first set easily. Vinci battled to win the second set and ultimately broke Williams' serve in the third set to set up one of the biggest upsets in this tournament's history.
Whereas some lower-ranked players would have buckled in the face of such overwhelming pressure on such a grand stage, Vinci would not. In fact, the 43rd-ranked woman in the world played like she had stared down adversity a thousand times before.
Serena, meanwhile, appeared unnerved in the final games of the third set. A trainer treated her right ankle in the final changeover, and Williams seemed to be paying attention to it in the previous game. But if the ankle gave her any trouble, she didn't say so.
"I think she played literally out of her mind," a visibly disappointed Williams said after the match. "She didn't want to lose today."
After putting away the final point, an exuberant Vinci raised her arms and flashed a big smile. Serena -- and all 22,500 at Arthur Ashe Stadium -- were stunned.
The Italian called it, "the best moment of my life."
The wildly charismatic Vinci played to the crowd during and after the match, and even apologized in a post-match interview for ruining Serena's Grand Slam and New York's premier tennis tournament.
"Well, [I'm sorry] for the American people, for Serena for the Grand Slam and everything. But today is my day. Sorry, guys," she said, which was met with a roar of applause from the crowd.
Friday's upset assures that it will be at least another year before anyone can challenge the 27-year-old record of former women's No. 1 Steffi Graf -- who remains the last player to capture a calendar-year Grand Slam, in 1988. Only three players in tennis history have accomplished the feat.
"She was three sets away. It just shows you how difficult it is to win the Grand Slam," former player and ESPN commentator Mary Jo Fernandez said. "You have to feel for Serena because she's been under the microscope every step of the way."
Vinci has won five career Grand Slam titles in women's doubles, but she has never even appeared in a singles major final. Most didn't expect that to change Friday, and odds-makers listed her as a 300-to-1 underdog to Williams -- a factoid that Vinci herself seemed shocked by.
"Really?" she responded, wide-eyed, to the ESPN reporter who informed her -- before turning to her coach and asked if he'd heard about that. But honestly, she admitted, even she didn't expect to beat the most dominant player in women's tennis.
"When I woke up [today] I said, 'I have a semifinal today. Try to enjoy. Don't think about Serena,'" she recalled after the match. "But I didn't expect that I would win."
Vinci's previous best at a Grand Slam event is a fourth round appearance -- three, in fact, at Wimbledon and the French Open in 2012 and 2013. This year, she was bounced in the first round at both of those tournaments -- and only reached the second round at January's Australian Open.
Friday's spectacular upset sets up an all-Italian U.S. Open women's final Saturday -- the first in history. Vinci will play 26th-seeded Flavia Pennetta, who easily defeated tournament No. 2 Simona Halep of Romania earlier Saturday, 6-1, 6-3.