Katerina Siniakova

Kateřina Siniaková (Czech pronunciation: [ˈkatɛr̝ɪna ˈsɪɲakovaː]; born 10 May 1996) is a Czech professional tennis player. She is a former world No. 1 in doubles.

Siniaková is a seven-time Grand Slam champion in women's doubles, partnering fellow Czech Barbora Krejčíková, having completed the career Super Slam in the discipline. The pairing also finished runners-up at the 2021 Australian Open, and Siniaková reached the final at the 2017 US Open with Lucie Hradecká. She became world No. 1 for the first time in October 2018, and has held the top ranking in doubles for a total of 115 weeks, the sixhth highest total since the beginning of the WTA rankings. Siniaková has won 24 doubles titles on the WTA Tour, including the 2021 WTA Finals and three at WTA 1000 level.

In singles, Siniaková reached her career-high ranking of world No. 31 in October 2018, and has won five WTA titles, at the Shenzhen Open and Swedish Open in 2017, the Slovenia Open in 2022, and the Bad Homburg Open and Jiangxi Open in 2023. Her best major result was at the 2019 French Open, upsetting world No. 1 and reigning US and Australian Open champion Naomi Osaka en route to the fourth round; she has also reached the third round at seven other major tournaments.

Siniaková was part of the Czech team which won the 2018 Fed Cup, and also won doubles gold at the 2020 Tokyo Olympics alongside Krejčíková.