The U.S. Open men's and women's singles competitions continued Monday as the second group of players began their campaigns at the final Grand Slam of the year, held at the USTA Billie Jean King National Tennis Center in New York.

Earlier, seven-time Grand Slam winner Venus Williams took Karolina Muchová (11) to a decider before losing 6-3, 2-6, 6-1, while Madison Keys (6) was stunned in three sets by world No. 82 Renata Zarazúa.

Carlos Alcaraz and Mirra Andreeva were among the big winners on Day 2 of the 2025 US Open. Both players booked their spot in the second round with convincing wins.

Williams competed well and tested Karolina Muchova before falling short in three sets in their US Open first-round match.

Venus Williams will be the first 45-year-old to compete at the US Open since 1981 when she faces Karolina Muchova on Monday.

The Russian pairing of Mirra Andreeva and Daniil Medvedev came out on top against the Serbian duo of Olga Danilovic and Novak Djokovic. Venus Williams has won multiple titles in women's singles and doubles at the US Open during her career, although a mixed doubles title has remained elusive.

Williams, who turned professional in 1994, was the oldest singles player at the tournament since Renee Richards, who was 47, in 1981.

Defending champion Jannik Sinner and 2022 winner Iga Swiatek will get their campaigns underway in the US Open 2025 on Day 3. Day 2 witnessed Carlos Alcaraz beating Reilly Opelka and Venus Williams losing her opener to Karolina Muchova.

Iga Swiatek is trying to do something no woman has done since Serena Williams in 2012: win the U.S. Open and Wimbledon in the same season.