The US Open 2026 officially got underway in New York on Sunday, with the singles competition beginning under bright skies at Flushing Meadows and a record $108 million (£80 million) prize purse setting the stage for the final Grand Slam tournament of the year.The opening day brought together some of the biggest names in tennis and a long list of intriguing first-round matchups. With the tournament once again being played across a 15-day schedule, spectators began arriving well before the first ball was struck at the USTA Billie Jean King National Tennis Center.The tournament's expanded format has been retained after organisers introduced an additional day to the schedule in 2025. The change was made in response to strong demand for tickets and growing interest in the year's final major.Fans arrive early for opening dayLong queues formed around the grounds before play began, reflecting the continued popularity of the New York Grand Slam.Italian star Jasmine Paolini was scheduled to open the day's action at 11 a.m. ET against Slovenia's Veronika Erjavec at Louis Armstrong Stadium. On the Grandstand court, Czech player Jiri Lehecka was due to face Spain's Pablo Carreno Busta.The weather provided a favourable backdrop for the start of the tournament. Sunny conditions and temperatures of approximately 75 degrees Fahrenheit greeted fans as they entered Flushing Meadows.For many spectators, the opening day offered the first chance to experience the atmosphere of a US Open that has increasingly become as much a major sporting event as a tennis tournament.Jessica Pegula leads American hopes on AsheThe first match on the tournament's biggest court, Arthur Ashe Stadium, featured American No. 1 Jessica Pegula.Pegula was scheduled to face Romania's Elena-Gabriela Ruse in the opening match on Ashe, giving the home crowd an immediate reason to get behind the American contender.The US Open has traditionally carried enormous importance for American players, and Pegula enters the tournament among the leading hopes for a deep run.Later in the day, attention was scheduled to turn to former champion Daniil Medvedev, who was due to meet France's Hugo Gaston.Medvedev won the US Open in 2021 and has remained one of the most prominent hard-court players of his generation. His opening match represents the beginning of another attempt to challenge for the title in New York.Djokovic gets another chance at historyThe biggest storyline surrounding the men's draw is once again Novak Djokovic.The 39-year-old Serbian, a 24-time Grand Slam champion, is scheduled to begin his campaign during the night session on Arthur Ashe Stadium against Argentina's Mariano Navone.Djokovic's pursuit of another major title has added extra intrigue to this year's tournament.World No. 1 Jannik Sinner is absent, while defending champion Carlos Alcaraz arrives in New York after a lengthy injury layoff. Those developments have created an unusually open-looking landscape at the top of the men's draw.For Djokovic, the circumstances represent another opportunity to add to a record-breaking Grand Slam collection.At 39, every major tournament carries additional significance for the Serbian star, whose longevity has already become one of the defining stories in modern tennis.Record US Open prize money announcedMoney is another major talking point at this year's tournament.The total US Open purse has reached $108 million, making it the largest prize pool in tennis history.The record figure reflects the enormous commercial value of the New York Grand Slam and comes as tennis continues to face questions about how revenue should be distributed among players.USTA chief executive Craig Tiley has said the increased purse is intended to ensure that players receive a fairer share of the revenue generated by the tournament.The prize-money increase is likely to attract attention throughout the fortnight, particularly as players outside the top ranks compete for potentially career-changing earnings.Why the US Open now runs for 15 daysThe 2026 tournament is being staged using the 15-day format introduced in 2025.Under the revised schedule, the opening round is spread across three days rather than being compressed into two. Organisers added the extra day following years of heavy demand for tickets.The longer schedule gives fans more opportunities to attend matches and allows organisers to spread the first-round workload across additional sessions.It also means that the opening weekend can feature more high-profile singles matches, helping build momentum earlier in the tournament.Venus Williams brings another major storylineThe women's schedule also features a remarkable moment involving Venus Williams.The 46-year-old American is set to close the night session against fellow American and wildcard entry Sofia Kenin.Williams' presence at the US Open remains significant given her extraordinary career and status as one of the most influential players in women's tennis.A meeting with Kenin provides another all-American storyline for the New York crowd, with the match expected to draw considerable attention as the opening day's action reaches its conclusion.An unpredictable final Grand Slam of the yearThe combination of an absent world No. 1, a defending champion returning from injury and Djokovic's continued pursuit of another major title has created plenty of uncertainty around the men's competition.The women's draw also promises its share of drama, with Pegula leading the American charge and a host of established stars looking to finish the Grand Slam season with a title in New York.With record prize money, packed stands and a longer opening schedule, the US Open 2026 has begun with plenty at stake.But as the first-round matches get underway at Flushing Meadows, the biggest question will ultimately be the simplest one: who will still be standing when the final weekend arrives?