As Serena Williams walked onto the court at the U.S. Open this week, the question was how the greatest player in modern tennis would handle the pressures of what she said could be her last Grand Slam tournament.

She had looked rusty and slow all summer, but over the course of four days and two prime-time matches, it looked like the 40-year-old just might mount a magical, storybook run for a 24th major title.

That dream ended Friday night in a heartbreaking three-set loss to Ajla Tomljanovic of Australia. To the end, the almost 24,000 fans who packed Arthur Ashe Stadium shouted and cheered her every point as she fought against an opponent who was 11 years younger.