One has been here before, but not for six years. The other is experiencing this for the very first time.

World No. 1s Rafael Nadal and Karolina Pliskova headline the seeds for the 2017 US Open.

For Nadal, it is his third time seeded No. 1 at the US Open, following 2008 and 2010, when he won the first of his two championships in New York. (The other came in 2013.) Pliskova is the top seed at a major for the first time after claiming the No. 1 spot in the WTA rankings at Wimbledon. Last year’s US Open runner-up is the fourth different women’s No. 1 seed in Flushing Meadows in the past eight years.

As the top seeds, Nadal and Pliskova will be placed at the opposite end of the draw to No. 2 seeds Andy Murray and Simona Halep and therefore would not meet their closest rivals before the finals.

No seed can meet another seed until the third round, and no Top 8 seed can meet another Top 8 seed before the quarterfinals.

On the men’s side, world No. 33 Diego Schwartzman, No. 34 Adrian Mannarino, No. 35 Feliciano Lopez and No. 36 Robin Haase will take the 29, 30, 31 and 32 seeds following the withdrawals of defending champion Stan Wawrinka, two-time winner Novak Djokovic, 2014 finalist Kei Nishikori and world No. 11 Milos Raonic.

One member of the Big Four – the collective nickname given to Nadal, Federer, Murray and Djokovic – has been the No. 1 seed in New York every year since 2004.

In the women’s draw, Magdalena Rybarikova and Lauren Davis, ranked Nos. 33 and 34 in the rankings, will be seeded because of the absence of Serena Williams and Timea Bacsinszky.

The top seeds have performed well at the US Open in previous years, winning the men’s title 14 times in 49 tries in the Open era and finishing runner-up on 10 occasions. Among the women, the No. 1 women’s seed has captured 20 titles in New York and contested 10 other finals.

Seeding began at the U.S. Championships in 1922 and moved to its current system of 32 men and women in 2001.

The men’s and women’s singles draws will be made Friday, will the main draw running Aug. 28 – Sept. 10.

Men’s Seeds

1. Rafael Nadal
2. Andy Murray
3. Roger Federer
4. Alexander Zverev
5. Marin Cilic
6. Dominic Thiem
7. Grigor Dimitrov
8. Jo-Wilfried Tsonga
9. David Goffin
10. John Isner
11. Roberto Bautista Agut
12. Pablo Carreno Busta
13. Jack Sock
14. Nick Kyrgios
15. Tomas Berdych
16. Lucas Pouille
17. Sam Querrey
18. Gael Monfils
19. Gilles Muller
20. Albert Ramos-Vinolas
21. David Ferrer
22. Fabio Fognini
23. Mischa Zverev
24. Juan Martin del Potro
25. Karen Khachanov
26. Richard Gasquet
27. Pablo Cuevas
28. Kevin Anderson
29. Diego Schwartzman
30. Adrian Mannarino
31. Feliciano Lopez
32. Robin Haase

Women’s Seeds

1. Karolina Pliskova
2. Simona Halep
3. Garbiñe Muguruza
4. Elina Svitolina
5. Caroline Wozniacki
6. Angelique Kerber
7. Johanna Konta
8. Svetlana Kuznetsova
9. Venus Williams
10. Agnieszka Radwanska
11. Dominika Cibulkova
12. Jelena Ostapenko
13. Petra Kvitova
14. Kristina Mladenovic
15. Madison Keys
16. Anastasija Sevastova
17. Elena Vesnina
18. Caroline Garcia
19. Anastasia Pavlyuchenkova
20. CoCo Vandeweghe
21. Ana Konjuh
22. Shuai Peng
23. Barbora Strycova
24. Kiki Bertens
25. Daria Gavrilova
26. Anett Kontaveit
27. Shuai Zhang
28. Lesia Tsurenko
29. Mirjana Lucic-Baroni
30. Julia Goerges
31. Magdalena Rybarikova
32. Lauren Davis