World No. 20 Casper Ruud suddenly pulled out of the U.S. Open on Sunday, according to an announcement by the tournament, scratching his first-round match against Juan Manuel Cerúndolo because of a lingering back injury. Ruud ranked as high as No. 2 just four years ago.
The withdrawal ends a rocky run into Flushing Meadows that began with a Cincinnati retirement, and it leaves open whether the back issue threatens more of his 2026 season.
Lucky loser Arthur Gea now takes Ruud’s spot in the men’s singles draw, according to the U.S. Open announcement.
Ruud was removed from the official order of play Sunday morning, according to Norwegian broadcaster NRK, which reported the back trouble first flared in mid-August.
In his career, Ruud owns a win over Novak Djokovic in the Monte-Carlo Masters 2024 semifinals — 6-4, 1-6, 6-4, his first career win over a world No. 1 making him the first Norwegian to beat a No. 1 in ATP rankings history, since 1973.
He also defeated Carlos Alcaraz in the ATP Finals 2024 group stage by a 6-1, 7-5 score, his only win over Alcaraz in six attempts.
Casper Ruud’s Back Injury Timeline
The pain traces to Cincinnati on Aug. 16, when Ruud retired against Christopher O’Connell at 7-5, 1-2 after a medical timeout for lower-back pain — this despite leading 5-2 in the opening set, according to French daily L’Équipe.
“I tweaked my back in practice the day before,” Ruud wrote on Instagram at the time, adding that he could not move freely.
The back held up long enough for Ruud to finish mixed doubles at Flushing Meadows. He and Diana Shnaider beat Jessica Pegula and Taylor Fritz in the first round before losing a tight quarterfinal to Mirra Andreeva and Andrey Rublev.
Shnaider became his partner only after Iga Swiatek withdrew from the event to rest.
By August 27, doubt about Ruud’s Open prospects crept back in. Footage showed Ruud cutting a practice session short with Tomás Martín Etcheverry after roughly 50 minutes. He “couldn’t serve” and even groundstrokes caused “considerable pain,” read a social media post cited by Tennis365 reporter Richie Mills.
Casper Ruud’s Ranking and U.S. Open Outlook
Ruud entered the tournament seeded 19th, landing in the same quarter as Alexander Zverev, according to injury tracker RotoWire. His singles ranking sat at No. 20 in the world this week, according to ESPN.
That’s a steep drop from his peak. Ruud reached No. 2 on September 12, 2022, after that year’s U.S. Open final, and spent 113 consecutive weeks in the top 10 between September 2021 and November 2023, according to ATP Tour rankings history.
Born Dec. 22, 1998, in Oslo, Ruud turned pro in 2015 and is coached by his father, former tour pro Christian Ruud. He is the highest-ranked player in Norwegian history and the first Norwegian man to win an ATP title, reach a Grand Slam final and qualify for the ATP Finals, according to his U.S. Open player profile.
Ruud has 14 ATP singles titles, 12 on clay, including last year’s Madrid Masters on clay. The back injury joins a log that isn’t chronic by tour standards but keeps resurfacing badly — an ankle pulled him from the 2022 Australian Open, and a painful left knee bothered him during a 2025 French Open loss to Nuno Borges.
A deep run looked unlikely even before the withdrawal. Ruud carried a 25-16 record into New York with zero titles in 2026, and his hard-court form had cratered, including a third-round loss to João Fonseca in Toronto. His best U.S. Open results since that 2022 final are fourth- and second-round exits.
Former World No. 2 Who Beat Alcaraz, Djokovic Suddenly Pulls Out of U.S. Open