Ranked 957th just last month, Sloane Stephens won the United States Open on Saturday, completing one of the most remarkable comebacks in a sport where comebacks are the coin of the realm.
Stephens, an unseeded 24-year-old, defeated the No. 15-seeded Madison Keys, her American contemporary, 6-3, 6-0.
It was the first Grand Slam singles final for both women, who have been friends since their junior days and have played on Fed Cup teams and Olympic teams together.
But this match in Arthur Ashe Stadium was a shared experience on another level. Stephens’s resurgence since returning in July from foot surgery has been astonishing in its speed, and Keys has made a convincing comeback of her own after two operations on her left wrist in the past 10 months.
Tabbed as a future No. 1 by Serena Williams, Keys, 22, is arguably the most powerful player in women’s tennis.
Stephens is arguably the quickest and also has ample punching power. She was able to prevail in a duel that has a chance be replayed on the game’s big stages in the years to come.
“I should just retire now,” Stephens said during the trophy ceremony. “I told Maddie I’m never going to be able to top this. I mean talk about a comeback.”
Maddie is Keys’s nickname, and though their first Grand Slam final was no classic as the huge-hitting Keys repeatedly made errors from the baseline, it was a touching occasion after it ended.
Stephens was exultant after clinching the victory, but she soon tempered her celebration, walking to the net and sharing an extended embrace and intense conversation with the emotional Keys, who was in tears.
After visiting the players box to celebrate with her coach and her mother, Stephens sat down next to Keys before the trophy ceremony. They chatted and joked with each other as they awaited the prizes. It was something the Williams sisters have done for years after their major finals.
“I told her I wish there could have been a draw,” Stephens said of Keys.
For now, Stephens, who will rise into the top 20 from No. 83, is the first American woman not named Williams to win a Grand Slam singles title since Jennifer Capriati at the 2002 Australian Open. Stephens also joins an esteemed list of African-American winners of the U.S. championship, which began with Althea Gibson 60 years ago.
Stephens was born in Coral Springs, Fla., in 1993, the year before Venus Williams turned professional (Serena Williams would follow suit in 1995). But in her early years, Stephens was actually a bigger fan of Kim Clijsters.
Her mother is Sybil Smith, a former leading swimmer at Boston University. Her father is John Stephens, a former N.F.L. running back with the New England Patriots. Her parents split early in her life, and she had little contact with her father, who died in a car accident in September 2009.
Stephens was playing in the junior event at the U.S. Open at the time. She left the tournament to attend the funeral and then returned.
She has long been considered a potential Grand Slam champion and has worked with some of the game’s leading coaches, including Nick Saviano, Paul Annacone, Thomas Hogstedt and, through the United States Tennis Association, David Nainkin.
She reached the Australian Open semifinals in 2013, beating Serena Williams in the quarterfinals. But she struggled with consistency and played with a style that many analysts considered too defensive. She has come into her own by finding a renewed passion for the game after an 11-month injury layoff.
“There’s a different look in her eyes since she came back,” said Chris Evert, a former No. 1 player who has known Stephens since she was a junior.
Now working with the coach Kamau Murray, Stephens is the lowest-ranked player to win the women’s title at the U.S. Open in the Open era. Clijsters, returning after the birth of her first child, won the event in 2009 without a ranking.
But Stephens, who reached the semifinals in Toronto and Cincinnati before arriving in New York, was a clear threat coming into this tournament despite being unseeded.
Now, she is a Grand Slam champion.