Carlos Alcaraz will start his US Open title defence against Russia's Roman Safiullin in the first serious examination of his fitness following a long-term wrist injury.
Second seed Alcaraz, who won the men's title in New York last year, has not played a competitive singles match for more than four months because of inflammation in his playing right wrist.
Despite his lack of action, the 23-year-old Spaniard is still considered by many as the favourite to triumph again - particularly because his great rival Jannik Sinner is not playing due to a knee injury.
The pair may have been a cut above the rest of the tour for the past two seasons, but Alcaraz coming back from a prolonged absence with such a delicate injury and beating the rest of the field - even though he is a generational talent - would be remarkable.
The seven-time major champion missed this season's French Open and Wimbledon as a result of the injury, which did not require surgery, before making his return to court in the US Open mixed doubles alongside Serena Williams earlier this week.
Wearing a long compression sleeve on his right arm, Alcaraz did not look totally convincing in the exhibition-like event. Understandably, he appeared to be holding back on his serve and return as he eased himself back into matchplay.
There is no doubt that a Grand Slam singles bout played over five sets will be another step up physically. Safiullin, with a hefty serve and attacking groundstrokes, is not an ideal opponent to start against.
The 29-year-old Russian, who reached the Wimbledon fourth round last month before falling to Novak Djokovic, is likely to take time away from Alcaraz, test the Spaniard's durability at the baseline and generally make him feel uncomfortable.
Predicting how Slam draws will pan out is always a fool's errand, but if Alcaraz does get past Safiullin and goes as far as the fourth round, there are more potential opponents who appear daunting given the length of his absence.
If you analyse Alcaraz's projected draw by the seedings, he could face rock solid American Tommy Paul or unpredictable Kazak Alexander Bublik in the last 16.
Athletic Frenchman Arthur Fils and huge-serving Ben Shelton are potential quarter-final opponents. Djokovic could lie in wait in the semi-finals.
Nobody outside of Alcaraz and his core team knows how his wrist is likely to stand up to the rigours of playing five-set matches in the heat of a Grand Slam tournament.
A challenging start at Flushing Meadows and a potentially intimidating second week will tell us.
Who have the other big names drawn?
Djokovic's latest quest for a standalone record 25th Grand Slam singles title starts against Argentina's Mariano Navone.
If he gets through that match, the 39-year-old Serb faces a challenging second-round match against either Italy's Matteo Berrettini - who he beat in the 2021 Wimbledon final - or three-time major champion Stan Wawrinka, in what will be the final major of the Swiss player's career after he was given a late wildcard.
Germany's Alexander Zverev, promoted to top seed after Sinner withdrew with a knee injury, faces Italy's Lorenzo Sonego in his opening match.
In the women's draw, defending champion Aryna Sabalenka starts against Colombia's Camila Osorio.
Sabalenka goes into the US Open having topped the WTA rankings for 97 weeks, but knows her place remains under threat from reigning Australian Open champion Elena Rybakina, who has been drawn against American teenage wildcard Thea Frodin.
Two-time champion Venus Williams, 46, has been given a wildcard despite losing all 10 of her matches this season and faces 2020 Australian Open champion Sofia Kenin in the first round.
Mensik & Muchova win US Open mixed doubles title
Wawrinka given late wildcard for US Open farewell
Who will the British players face?
Surprise Wimbledon semi-finalist Arthur Fery returns to the Grand Slam stage with a first-round match against Italian 13th seed Lorenzo Musetti.
Fery, 24, produced a career-changing run at the All England Club in July, propelling him into the world's top 40 for the first time and securing his US Open debut in the process.
Fery narrowly missed out on a seeding and, having been drawn against 2025 quarter-finalist Musetti, has received a tough opener as a result.
A lot of attention will be placed on how the world number 37 fares in New York, where he leads a rather sparse British contingent in the absence of injured pair Jack Draper and Emma Raducanu.
Draper, who reached the 2024 semi-finals, withdrew last week because of a long-term arm injury, while 2021 champion Raducanu remains sidelined with the shin fracture which also forced her to miss Wimbledon.
British men's number one Cameron Norrie did manage to sneak into the seedings and the 29th seed plays France's Luca van Assche in his opening match.
Jan Choinski is currently the only other Briton in the men's draw after reaching the world's top 100 for the first time in June at the age of 30.
Choinski's reward for earning direct entry into a Grand Slam other than Wimbledon for the first time is a first-round contest with Dutch player Botic van de Zandschulp, who famously beat Alcaraz in the second round of the 2024 US Open.
Katie Boulter is the only Briton guaranteed a place in the women's draw through her ranking and meets American wildcard Carol Young Suh Lee, who is ranked 143rd in the world.
If Boulter wins a Grand Slam match for only the second time this year, the 30-year-old could meet Wimbledon finalist Karolina Muchova in the second round.
Six more Britons - Francesca Jones, Jacob Fearnley, Toby Samuel, Heather Watson, Harriet Dart and Harry Wendelken - aim to reach the main draws by winning their final qualifying matches on Thursday.
Watson to face fellow Briton Dart for US Open spot
Other notable first-round matches
Maja Chwalinska [20] (Pol) v Taylor Townsend (US)
Katie Volynets (US) v Linda Noskova [6] (Cze)
Jessica Pegula [3] (US) v Elena-Gabriela Ruse (Rom)
Zeynep Sonmez (Tur) v Coco Gauff [4] (US)
Iga Swiatek [8] (Pol) v Wang Xiyu (Chn)
Thea Frodin (US) v Elena Rybakina [2] (Kaz)
Full women's singles draw, external
Rafael Jodar [12] (Spa) v Thanasi Kokkinakis (Aus)
Felix Auger-Aliassime [3] (Can) v Rinky Hijikata (Aus)
Adolfo Daniel Vallejo (Par) v Gael Monfils (Fra)
Marin Cilic (Cro) v Andrey Rublev [23] (Rus)
Stefanos Tsitsipas (Gre) v Arthur Fils [10] (Fra)
Full men's singles draw, external
