The 2025 US Open Fan Week is now officially underway. In the midst of qualification matches and practice rounds, the courts of the USTA Billie Jean King National Tennis Center saw a boost in star power as NYC Mayoral candidate Zohran Mamdani stopped by to enjoy some tennis action.The US Open is the last Grand Slam of the season and as such it carries an air of incredible excitement. Each year, the Major is kicked off with ‘Fan Week’, a seven-day long event where tennis enthusiasts can experience the culture and access the USTA Billie Jean King National Tennis Center for free.The highlight of the 2025 Fan Week will be the mixed doubles competition, but other exciting events include a US Open Block Party, an evening happy hour and more. Recently, NYC Mayoral candidate, Zohran Mamdani attended ‘Fan Week’ showcasing the popularity of the event.US Open 2025: Defending champion Jannik Sinner's participation in doubt after shock Cincinnati Open final retirementSinner at the Cincinnati Open (Image Source: Getty)The 2025 US Open promises to bring with it an exciting amount of tennis action. However, the men's singles draw at the event might be missing one major name.On Monday, August 18, World No.1 Jannik Sinner was in action at the Cincinnati Open finals against longtime rival Carlos Alcaraz, when he retired from the match after just minutes of play. In his post match speech, the Italian apologised to the crowd, explaining,“Usually I start with the opponent but today I have to start with you guys [the crowd]. I’m super super sorry to disappoint you. From yesterday I didn’t feel great. I thought I would improve during the night. It came up worse. I tried to come out and make it at least a small match but I couldn’t handle more. I’m very very sorry for all of you. I know some of you on Monday maybe had to work or do something else, so I’m very very sorry.”He went on to congratulate Alcaraz and wish him the best for the upcoming Major, adding,“Of course, Carlos, congrats. Another title. For sure not the way you wanted to but it's amazing what kind of season you are producing. Congratulations to you and your whole team. You're doing amazing. Keep it up. I wish you only the best for the US Open and obviously the rest of the season.”In 2024, Jannik Sinner lifted the US Open trophy after beating Taylor Fritz in the final. The Italian is undoubtedly one of the most dominant performers of the hard court season, but after his withdrawal from the Cincinnati Open finals, fans remain doubtful about his participation in New York.