For Serena Williams, this U.S. Open is a chance to make history; for Roger Federer, it's a chance to preserve it.Geoff Burke / USA Today Sports / Reuters

Serena Williams and Roger Federer are two of the greatest tennis players of all time. That idea has been reiterated so often by journalists and commentators, by current and former players, that it’s assumed an almost self-evident quality. Williams has broken records and wowed fans for years on the women’s tour; Federer has done the same on the men’s. Federer is 38 years old, while Williams will turn that age this September. Both are in the twilight stages of illustrious careers, and both enter the 2019 U.S. Open, which begins play today, as nominal contenders. Which is to say you have to at least pencil them in as potential winners—even though there’s a solid chance they’ll go home empty-handed.

Neither Williams nor Federer needs to win another grand-slam title to justify their respective legacies. But while both have already achieved so much, they still have something significant at stake, which makes them fascinating presences at this year’s U.S. Open.  

For Williams, it’s the chance to make history. If she wins, she’ll tie Margaret Court’s record of 24 grand-slam singles titles, the most of any tennis player. For Federer, it’s the need to preserve history. He currently holds 20 grand-slam singles titles, the most for a male player. But Rafael Nadal and Novak Djokovic—his two greatest rivals—are on his heels. Nadal has 18 grand-slam singles titles, Djokovic 16. Both are notably younger than Federer and playing tennis at the highest level (Djokovic is currently ranked No. 1 in the world while Nadal is No. 2), meaning they each have a legitimate shot to surpass the Swiss maestro in tennis’s most important statistical category.

Still, arguments for a player’s G.O.A.T. status have never relied solely on statistical justification; the full picture of an athlete’s career matters, too. Williams’s narrative has always been heavily grounded in the circumstances of her ascension. She’s the quintessential outsider-turned-icon, having overcome remarkable odds to enter a sport that didn’t welcome her with open arms before proceeding to dominate it. She began playing tennis during her childhood in Compton, California, far from a traditional hotbed of tennis talent, where she worked under the instruction of her father and coach, Richard Williams. She spent the early stages of her career in the shadow of her big sister, Venus Williams, a former world No. 1 who has won seven grand-slam singles titles of her own.

On the court, Serena Williams combines raw power with courageous shot making in a manner that tends to overwhelm even her most talented opponents. In the first round of this year’s U.S. Open, she will face the five-time grand-slam singles champion Maria Sharapova, an accomplished player whose game breaks down just about every time she faces Williams. Everything that Williams has achieved—often despite inordinately hostile conditions—affirms her virtuosity.

In the case of Federer, it’s the specific way he plays the game that’s always enthralled so many. The quality of his shot making and the seeming ease with which he annihilates competitors are unparalleled in the history of men’s tennis. There are legions of YouTube playlists documenting the incredible winners Federer has hit over the years. As the American player Sam Querrey so succinctly put it, “He hits shots that other guys don’t hit,” and Federer tends to do so without ever evincing a sense of effort. Even John McEnroe, who in his day was considered the game’s greatest shot maker and a true artist with a racket, made tennis look grueling. Federer is the rare athlete capable of inspiring a literary wunderkind to liken the experience of watching him play to religious fervor, and a dance critic to rhapsodize about the grace of his physical presence. Federer’s staunchest advocates present him as less an athlete than as the Platonic ideal of a sport in which aesthetic appeal holds special cachet.  

Unfortunately for them and their fans, Williams and Federer face uphill battles at the 2019 U.S. Open. Williams hasn’t won a grand-slam title since the 2017 Australian Open; she’s played in three grand-slam finals since then and lost each of those contests in straight sets. Federer hasn’t won a grand-slam title since 2018 and has failed to advance past the quarterfinals of the U.S. Open in each of the past two years. (Last year, Federer lost to the Australian journeyman John Millman in the fourth round, one of the few matches in which his tennis looked anything but effortless.) Should Williams advance to the final of the women’s draw, she’ll have to overcome her recent struggles in culminating matches of majors. For his part, Federer will have to prove that he has put the 2019 Wimbledon final, which he lost to Djokovic despite holding two match points on his serve, behind him.   

It’s not every day that an athlete who has already achieved the unprecedented steps onto the field of play with so much on the line, but that’s the best way to describe Serena Williams and Roger Federer at the onset of the U.S. Open. These two champions are as compelling now as they’ve ever been.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.