Who is Katarina Siniakova, the new partner of Jannik Sinner

At the 2025 U.S. Open, Jannik Sinner, world number one and a symbol of Italian tennis, will be starring not only in singles, but also in the mixed doubles draw. At her side will be Katerina Siniakova, her new partner in adventure on the courts of Flushing Meadows.

Born in 1996 in Hradec Kralove, Czech Republic, Siniakova is one of the most successful tennis players of her generation. A doubles specialist, she captured the top spot in the WTA world rankings, holding it for a total of 161 weeks, an achievement that places her among the discipline’s best ever performers. Shining in her palmarès are 30 WTA doubles titles, including the “Career Golden Slam” together with Barbora Krejčíková: all Grand Slam events, the Olympic title and the WTA Finals.

Along with her successes in pairs, Siniakova also took personal satisfaction: in singles she won 5 tournaments and reached the number 27 position in the world ranking in June 2024. No less notable is her track record in mixed doubles, which saw her win Olympic gold in Paris 2024 and the title at Wimbledon 2025.

Katerina is the daughter of a Czech mother and a Russian father, a former boxer and her first coach. Her younger brother Daniel also pursued a professional tennis career. Away from the court, she enjoys reading mystery and science fiction novels, listening to music, and nurturing a dream of meeting American pop star Taylor Swift.

Sinner’s choice to team up with Siniakova comes after the forfeit of U.S. Emma Navarro. Ahead of the U.S. Open, the Italian champion has thus found in the Czech tennis player a top partner, capable of bringing experience and tactical solidity to a draw traditionally full of surprises. Their debut is expected against the pair formed by Belinda Bencic and Alexander Zverev, an immediately challenging exam.