The U.S. Open commenced with thrilling matches at Flushing Meadows, highlighted by German fourth seed Alexander Zverev's victory over Maximilian Marterer and American Ben Shelton's win against former champion Dominic Thiem. Defending champions Novak Djokovic and Coco Gauff kicked off their title defenses, with Djokovic aiming to add to his accolades after his Olympic gold win. However, the day was overshadowed by Greek ninth seed Maria Sakkari's mid-match retirement due to a shoulder injury. The competition is set to be intense, with top players like Carlos Alcaraz and Jannik Sinner also vying for the title amid recent controversies. The day's weather was pleasant, with temperatures around 26 degrees Celsius, setting the stage for a captivating tournament ahead.