Breaking News: Serena Williams, Roberta Vinci, the U.S. Open and the tennis upset of the century….see more

Williams, 43, accomplished everything in her tennis career. She won 23 Grand Slam singles titles and an Olympic gold medal, with 73 singles titles in all.

She spent more than 300 weeks as world No. 1, including 186 in a row. Everything, but for the thing that awaited her a decade ago, in September 2015. She arrived in New York for the U.S Open on the doorstep of the sport’s crown jewel: the Calendar Grand Slam of winning all four major titles in a single year.

She had held all four twice before, including during that summer of 2015, when she had become a force of nature at 33 despite a patchwork of injuries, but now she was seven wins away from just about the only thing another woman had done that she had not.

Steffi Graf, who was finishing her career as Williams was starting hers, did it in 1988, adding an Olympic singles gold medal to make it a Golden Slam. As Williams moved through the draw, she won her first five matches for the loss of just two sets.

She secured a win over her sister, Venus, as nervy as those matches ever were. Some of her other rivals fell away in her wake, including two-time Wimbledon champion Petra Kvitová, who at the time was the last woman not named Serena Williams to win a Grand Slam.

By the time Williams took the court for her semifinal, world No. 2 Simona Halep had fallen to Flavia Pennetta, the No. 26 seed.