Serena Williams needs just two more wins in this year’s U.S. Open to tie Margaret Court’s all-time record of 24 Grand Slam titles. The record would be impressive on its own, but it’s even more notable for the strength of her opposition: Williams has faced the best in the game, over and over, in the 20 years since she won her first major.

The 37-year-old captured her first major title at the U.S. Open on Sept. 11, 1999, beating Martina Hingis. Since then, 58 different players have ascended to the top 10, according to the WTA, and Serena has played 55 of them. She’s also played almost all of the women who have made it into the top 5 since her first title, facing 36 of the 37. And more of Williams’s opponents are likely to make their top 10 debuts soon: Bianca Andreescu, whom she faced in Toronto last month, is ranked 15th and could reach the top 10 for the first time after she won Wednesday in the quarterfinals of the U.S. Open.

Some of her former adversaries — players who made it atop the rankings in the past 20 years — have already retired, while Williams continues to compete for major titles. Justine Henin, who is 6-8 all-time against Williams, retired in 2008, staged a comeback in 2010 and left the game for good in 2011. Kim Clijsters, who was 2-7 against Williams, retired in 2012.

Somehow, Williams has continued to evolve despite facing a seemingly endless parade of young talent.

“I think the sport has come a really long way,” Williams said in her post-match press conference on Tuesday. “It’s the best work in the world that a woman can do in my mind.”

Serena’s staying power has been a thing of beauty. From 1999 to 2010, she won 13 major titles. She struggled in 2011 and early in 2012, missing large swaths of time with a foot injury and blood clots in her lungs. But after she started working with Patrick Mouratoglou in 2012, reworking some of her approach to the game and recovering from the injuries, Williams reversed her decline and played her best tennis yet. From 2012 to 2017, she won 10 Slams, an improbable count for her age. And, of course, Williams took a year off from the sport around the birth of her daughter in September 2017, skipping four straight Slams until last year’s French Open.

At the U.S. Open, she is close to another record. After beating Wang Qiang 6-1, 6-0 on Tuesday, Williams now has 100 match wins at the U.S. Open. If she wins the tournament without an opponent withdrawal, she will pass Chris Evert, who won 101 matches in her U.S. Open career.

Even among her historic achievements, a record 24th major victory for Serena will be on the minds of observers on Saturday. Since her last Slam victory in 2017, Williams has come close to the mark, reaching three finals in the past two years. Tonight, she will battle Elina Svitolina, who has beaten Williams once, at the 2016 Olympics in Rio de Janeiro. Svitolina hasn’t lost a set at the Open and has looked formidable. Still, Williams has a great opportunity this week to finally tie Court’s record, as none of the three other women left in the U.S. Open — Svitolina, Andreescu and Belinda Bencic — has ever won a major.

“It feels good,” Williams said. “This is what I’ve been training for.”