“It is your passion that powers this place; your energy that amps up its electricity. Your collective heart provides its singular soul,” said Billie Jean King, the iconic American player and winner of 39 Grand Slam titles, at the start of this year's United States Open, which will be attended by the public after last year's desert edition during the pandemic.

Austria's Dominic Thiem and Japan's Naomi Osaka will fight to defend their crowns at Flushing Meadows, in a full-capacity tournament that always generate many emotions and more than one surprise. Here are 10 facts to know about the last Grand Slam of the year.

1. The youngest player (18 years old) to participate in this tournament is Carlos Alcaraz, from Spain, born in 2003. For his part, the oldest (42) is Croatia's Ivo Karlovic who was born in 1979 and will play his seventeenth U.S. Open.
2. It's a great year for players under 20, with the participation of the North American Coco Gauff, Canada's Leylah Fernandez, Britain's Emma Raducanu, Denmark's Clara Tauson, and Colombia's María Camila Osorio, who all qualified for the second round of the tournament.
3. A first round upset came from North American Maxime Cressy, who eliminated the ninth seed of the tournament, Spain's Pablo Carreño Busta.
4. Serbian Novak Djokovic is seeking his 21st Grand Slam title in the United States and his fourth in the Big Apple.
5. Neither Roger Federer nor Rafael Nadal will compete in New York.
6. Germany's Alexander Zverev, last year's finalist, and recent winner of the Tokyo 2020 gold medal and the Cincinnati Masters 1000, has a 12-match winning streak following his first-round win against American Sam Querrey. 
7. Although it was initially been proposed to allow entry to the public without requiring a COVID-19 vaccine, it was later decided that fans 12-and-up, will be required to have at least one dose of the vaccine. No negative COVID tests will be requested and no temperature checks will be made. The use of the mask will be required when the roof is closed on the main court of the Arthur Ashe Stadium. Players are not required to be vaccinated.
8. The public has been asked to avoid approaching players to request autographs, as is often done sometimes at the end of matches.
9. #BeOpen is the Grand Slam side event that brought together a diverse and “underrepresented” group of artists on display outside Arthur Ashe Stadium.
10. Forty-six countries will be represented at the 121st edition of the U.S. Open.