Barty, a 25-year-old from Australia, joins Serena Williams, Steffi Graf, Martina Navratilova and Chris Evert as the only women to lead the year-end tennis rankings three straight times.
This week is Barty’s 95th in a row atop the WTA and 102nd overall.
Barty’s title at the All England Club in July was her second at a Grand Slam tournament. She also won the 2019 French Open and soon after moved up to No. 1 for the first time in June of that year.
Siniakova is coming off a title Wednesday at the season-ending WTA Finals in Guadalajara, México, alongside doubles partner Barbora Krejcikova. Siniakova, a 25-year-old from the Czech Republic, terminó 2018 as a co-No. 1 in doubles with Krejcikova.
They won the French Open and a gold medal at the Tokyo Olympics together, part of Siniakova’s total haul of five doubles titles in 2021.
Barty also collected five titles, yendo 42-8. She last competed at the U.S. Open in September and announced in October she was done for the year and would not enter the WTA Finals.