Serena Williams' bid for a rare calendar-year Grand Slam came to a shocking halt at the US Open when the defending champion suffered one of the greatest tennis upsets to unseeded Italian Roberta Vinci.
The 32-year-old Vinci ended Williams' run of three straight US Open titles and her bid to become the fourth woman to sweep all four grand slam singles titles in the same year with a 2-6 6-4 6-4 win that stunned the Arthur Ashe Stadium crowd.
For world number one Williams, it marked the first time she lost to Vinci in five career meetings after a string of easy straight-set wins against her.
"I thought she played the best tennis in her career," Williams said about her 43rd-ranked opponent who was playing in her first grand slam singles semi-final.
"You know, she's going for it at a late age. Actually, I guess it's inspiring. I think she played literally out of her mind."
Today is my day. Sorry guys
Vinci's extraordinary win set up an all-Italian women's final on Saturday against 33-year-old Flavia Pennetta, who routed second seed Simona Halep of Romania 6-1 6-3.
"This is an incredible moment for me," Vinci said after taking a long moment to compose herself for the on-court interview. "It's amazing. It's like a dream. I'm in the final. I beat Serena."
Vinci, a winner of five grand slam doubles titles, took advantage of some loose points from the American, who appeared to feel the pressure of her pursuit of tennis history.
The beaming Vinci was almost apologetic about ending the single season Grand Slam run of Williams.
"Sorry guys," Vinci said.
"For the American people, for Serena, for the Grand Slam and everything. But today is my day. Sorry guys," said the Italian, who was showered with an Arthur Ashe ovation.
Earlier, Pennetta crushed Romanian second seed Halep 6-1 6-3 toput herself into her first grand slam final.
Pennetta, 33, entered the contest as the clear underdog but the 26th seed showed her experience and was not overwhelmed on the big stage having reached at least the quarter-finals at Flushing Meadows in six of the last seven years.
"It's amazing. I didn't think to be so far in the tournament," said Pennetta.