"It's really amazing. I mean, you totally prepare for this," she responded. "I was always one to say, 'I want to win the US Open. I want it.'"
After Leylah Fernandez, a 19-year-old from Canada, upset No. 2 seed Aryna Sabalenka in the US Open semifinals on Thursday, she sounded a lot like Williams in 1999: "Nothing's impossible. There's no limit to what I can do. I'm just glad that right now everything's going well."
Williams' match against 18-year-old Martina Hingis of Switzerland was the last time two teenagers met in a major final. Fernandez and 18-year-old Emma Raducanu of Britain will change that on Saturday in the US Open women's final -- bringing a trait also possessed by the teens who broke through 22 years ago.
"[In 1999], I saw the same composure with [Williams and Hingis]," said Rennae Stubbs, a former player and ESPN tennis analyst. "Great champions must have composure. They must have the ability to handle the big moments, and those two had incredible careers after that."
No matter who wins the title come Saturday, a new teenager will be crowned the US Open champion. And the tournament boasts a long list of teen champs who have gone on to have successful careers, the latest being Canada's Bianca Andreescu, who beat Serena Williams in 2019.
As Fernandez and Raducanu seek to make history of their own, here is a look at all the teenagers who have won the US Open in the Open era.
Tracy Austin, 1979 and 1981 US Open
Age: 16 years, 270 days (1979)
At 16 years and nine months, American Tracy Austin became the youngest US Open champion in the Open era. Her accomplishment is even more incredible because of the player she beat: four-time defending champion Chris Evert -- in straight sets, 6-4, 6-3. Two years later, Austin, then the third seed, beat Martina Navratilova in three sets, 1-6, 7-6, 7-6, to reclaim the title. The two US Open titles ended up being the highlights of her career.
Steffi Graf, 1988 US Open
Age: 19 years, 89 days
The year Steffi Graf had in 1988 was one for the history books. At 19, she became the first tennis player to win a Golden Slam, winning all four Grand Slam titles, plus the Olympic gold medal in Seoul, South Korea. She remains the only person in the history of the sport to have accomplished the feat. She beat Gabriela Sabatini 6-3, 3-6, 6-1 in the US Open, becoming the third woman after Margaret Court and Maureen Connolly Brinker to win a calendar Grand Slam.
Pete Sampras, 1990 US Open
Age: 19 years, 29 days
The only male tennis player on this list, 19-year-old Sampras was seeded No. 12 coming into the 1990 US Open, having lost in the first round of that year's Wimbledon. He largely flew under the radar before beating Ivan Lendl in the quarterfinals and John McEnroe in the semis. In the final, he beat Andre Agassi in straight sets, 6-4, 6-3, 6-2, winning his first Grand Slam title. The win launched his career, and he went on to win a then-record 14 major titles, which was surpassed in 2009 by Roger Federer.
Monica Seles, 1991 and 1992 US Open
Age: 17 years, 280 days (1991)
By the time she was 17 and had reached the 1991 US Open, Seles had already won two major championships. In the US Open, Seles, who was ranked No. 2 in the world, beat then-No. 1 Martina Navratilova in straight sets 7-6, 6-1, winning her third Grand Slam title and replacing Navratilova as the world No. 1. She followed a massive year in 1991 with an even better year in 1992, reaching all four Grand Slam finals, becoming the sixth woman to do so, and defending her US Open title, beating Spain's Arantxa Sanchez Vicario 6-3, 6-3, to win her seventh Grand Slam title by the time she was 19.
Martina Hingis, 1997 US Open
Age: 16 years, 342 days
At just 16, Hingis reached the finals of all four Grand Slams in 1997, becoming the youngest woman and the seventh woman in history to do so. She also became the youngest woman to win three major tournaments in a year in 1997. In the finals of the US Open, she had a dominant win against Venus Williams 6-0, 6-4, and did not lose a single set the entire tournament.
Serena Williams, 1999 US Open
Age: 17 years, 350 days
Williams beat then-No. 1 Martina Hingis in straight sets, 6-3 7-6, which propelled her to global stardom overnight. She became the first African-American woman to win a Grand Slam title in the Open era.
"I was in the locker room, because I was still playing doubles, and Serena came in ahead of her [third-round] match against Kim Clijsters. She said, 'I'm winning this match because you did well in the semis [at Wimbledon] and I'm going to win this tournament and beat you,'" recalled former tennis player Alexandra Stevenson, who reached the semifinals of Wimbledon in 1999. "So I was not surprised she won [the] US Open at all. Serena likes to do stuff like that. She's very competitive and she turned it around and won the Open."
Svetlana Kuznetsova, 2004 US Open
Age: 19 years, 76 days
Kuznetsova dominated the entire tournament, losing only one set -- to Lindsay Davenport in the semifinals -- in the entire tournament before winning the title. She beat fellow Russian Elena Dementieva 6-3, 7-5, becoming the third Russian woman after Maria Sharapova and Anastasia Myskina to win a Grand Slam title.
Maria Sharapova, 2006 US Open
Age: 19 years, 144 days
After beating then-No. 1 Amelie Mauresmo, the 19-year-old Russian went up against Justine Henin, who became the eighth woman to make all four Grand Slam finals in a calendar year. Sharapova won the final in straight sets, 6-4, 6-4, becoming the second Russian teenager after Kuznetsova to win the US Open title. This was her second Grand Slam title after winning Wimbledon as a 17-year-old in 2004.
Bianca Andreescu, 2019 US Open
Age: 19 years, 83 days
Andreescu had a dream run at the 2019 US Open, beating then-No. 19 Caroline Wozniacki and Belinda Bencic en route to the final. There, she went up against multitime Grand Slam champion and crowd favorite Serena Williams, who was making a comeback after the birth of her daughter. Andreescu took the match in straight sets, 6-3, 7-5, denying Williams her 24th Grand Slam title and a chance to equal Margaret Court's record.
"For it to become a reality is so crazy," an emotional Andreescu said in her postmatch news conference. "I guess these visualizations really, really work."
Notable teen wins from the three other Grand Slams
Martina Hingis, 1997 Australian Open: Hingis won five titles before she turned 20, and it all started with the 1997 Australian Open when she was just 16. She beat Mary Pierce in straight sets, 6-2, 6-2, not losing a set the entire tournament. And she became the youngest woman to win a Grand Slam title since Lottie Dod won Wimbledon in 1887 -- 110 years before.
Rafael Nadal, 2005 French Open: At 19, Nadal beat Mariano Puerta 6-7, 6-3, 6-1, 7-5 to win his first French Open and first Grand Slam title. He followed that up with a record 13 French Open titles in his career.
Boris Becker, 1985 Wimbledon: Becker, 17, came in as an unseeded player, and beat three top-10 players to win his first Grand Slam championship. He became the first unseeded player to win Wimbledon.