US Open defending champs and No. 1 seeds Krejcikova and Siniakova knocked out in women's doubles

Marketa Vondrousova, of the Czech Republic, reacts during a match against Martina Trevisan, of Italy, during the second round of the U.S. Open tennis championships, Thursday, Aug. 31, 2023, in New York. (AP Photo/John Minchillo)

NEW YORK (AP) — Barbora Krejcikova and Katerina Siniakova, the top-seeded team and the defending U.S. Open women's doubles champions, were knocked out of the tournament Friday in the second round.

They lost 6-2, 6-3 to fellow Czechs Marketa Vondrousova, the Wimbledon singles champion, and Barbora Strycova, who won the doubles title at the All England Club.

Krejcikova and Siniakova completed a career Grand Slam with their victory last year at Flushing Meadows. That capped a dominant season in the major tournaments, winning all three they played. They were unable to defend their 2021 French Open title after Krejcikova tested positive for COVID-19.

Strycova came out of retirement this year after giving birth to a son and teamed with Hsieh Su-Wei of Taiwan to win their second Wimbledon doubles title.

The loss by Krejcikova and Siniakova leaves the third-seeded team of Americans Coco Gauff and Jessica Pegula as the highest seeds left in the tournament. No. 2 Elise Mertens and Storm Hunter were upset in the first round.