That is at the U.S. Open in New York.
The anticipation of a classic showdown inside Arthur Ashe Stadium is part of the lure of this year's Open, which begins Monday.
Federer won five consecutive U.S. Opens from 2004-08 and Nadal is a two-time champ, winning in 2010 and 2013.
The two veteran stars put on a show in a superb five-set Australian Open final won by Federer earlier this year. They have combined to win each of this year's previous three majors -- Federer also won Wimbledon while Nadal was victorious in the French Open.
Now the big stage in New York awaits Swiss legend Federer and Spanish icon Nadal.
Nadal is the No. 1 seed and Federer is No. 3. The lone down side is the two are on the same side of the draw, meaning they would have to square off in the semifinals.
But the way Nadal sees it is that he would prefer to face anyone but Federer.
"I know you want to hear the other way, that I would love to play with him," Nadal told reporters. "No, of course I understand that (it's) gonna be great for our history. It is true that we played in all (the other) Grand Slam finals. We never played here and for sure this year we are not going to play in finals. Finals are more special than semifinals, in that case."
Federer, who is chasing his 20th Grand Slam title, is OK with playing Nadal in the semis.
"I mean, I'd be happy to play him here," Federer told reporters. "We never played here in New York, so I think that would be fun for everybody involved. I mean, there is, like, I don't know, 60-plus players in between us that don't agree in our section that we should make it to the semis. We have our work cut out there.
"But, you know, I'd love to play Rafa here in New York. Hopefully it will be a night session. Hopefully that would be a great atmosphere and one again where we play great like at the Australian Open."
Bolstering each man's hope of another U.S. Open title is the absences of several of the tour's top players.
Last's year champion, Stan Wawrinka of Switzerland, won't be defending his crown due to a knee injury. Also missing are Canadian Milos Raonic and Japan's Kei Nishikori, both sidelined with wrist injuries.
Perhaps the biggest threat to Nadal and Federer is upstart German Alexander Zverev. The fourth-seeded Zverev defeated Federer in a title match in Cincinnati earlier this month.
Fifth-seeded Croatia Marin Cilic also figures to be a factor. He won the U.S. Open in 2014.
Nadal will face Serbian Dusan Lajovic in his first-round match. Federer meets American Frances Tiafoe.
On the women's side, there is a wide-open feel with six-time champion Serena Williams absent due to her pregnancy.
In addition, defending champion Angelique Kerber, the sixth seed from Germany, is experiencing a down year.
Karolina Pliskova of the Czech Republic is the top seed but she has never won a Grand Slam title. Pliskova lost to Kerber in last year's final.
"I don't want to put any extra pressure (on myself)," Pliskova said at a news conference. "I have enough pressure."
Romania's Simona Halep is the second seed and she also has never won a Grand Slam event.
Two-time Wimbledon champion Garbine Muguruza of Spain is seeded third and enters the tournament in top form.
Ukraine's Elina Svitolina, who has won five titles this season, is seeded fourth. Denmark's Caroline Wozniacki is fifth.
Venus Williams is seeded ninth and fellow American Madison Keys is No. 15.
Maria Sharapova received a wild-card entry and will face Halep in the opening round. The tournament represents Sharapova's first appearance in a Grand Slam match since the 2016 Australian Open. Sharapova tested positive for the banned drug meldonium in Australia and served a 15-month doping suspension.
Pliskova opens her pursuit of the crown against Magda Linette of Poland.
"I know it's going to be very difficult, with obviously so many girls playing for this (No. 1) position," Pliskova said. "But I think I have a good chance to stay there if I play well these two weeks."
Eight women have a chance to ascend to the No. 1 ranking based on their results at this U.S. Open. Halep, Pliskova, Muguruza, Svitolina, Wozniacki, Johanna Konta, Svetlana Kuznetsova and Venus Williams all could reach the top spot if the appropriate scenario plays out in New York.
The tournament concludes on Sept. 10.