Novak Djokovic faced an unexpected challenge in the second round of the US Open 2025, but ultimately secured his place in the third round. The world number 7, chasing a record-extending 25th Grand Slam title, overcame American qualifier Zachary Svajda in four sets. After dropping the first set 6-7 (5/7), Djokovic recovered to win the next three sets 6-3, 6-3, 6-1. Djokovic admitted he wasn't happy with his level of tennis early in the match but gave credit to Svajda for his high-quality play. Djokovic will face Cameron Norrie in the next round.

Aryna Sabalenka, the defending women's champion, is also stepping up her title bid. Sabalenka began her US Open campaign with a straight-sets victory over Rebeka Masarova. Sabalenka, who is aiming to win her third Grand Slam title, will face Polina Kudermetova in the second round. Sabalenka is looking to become the first woman to win back-to-back US Open titles since Serena Williams in 2014.

Carlos Alcaraz, the young Spanish star, is also a prominent figure at the US Open. Alcaraz, sporting a fresh buzzcut, is aiming to maintain the form he showed in his opening win against Reilly Opelka. Alcaraz faced Italian Mattia Bellucci in the second round. Alcaraz's new haircut has been a major talking point at the US Open, with some fans liking it and others not. Alcaraz himself has been amused by the reaction.

Other notable events on Day 4 of the US Open include Cameron Norrie's victory over Francisco Comesana. Norrie will now face Djokovic in the third round. Jack Draper withdrew from the tournament due to injury. Emma Raducanu earned her first US Open win since her 2021 title run. Taylor Fritz and Ben Shelton are spearheading US hopes of a first Grand Slam men's singles win since Andy Roddick's victory at the 2003 US Open.