of Krejčíková and Siniaková in both tournaments. During the summer, they reached another Premier 5 semifinal at the Canadian Open, this time losing to Krejčíková and Siniaková who were again the top seeds. Barty came close to defending her title at the US Open. In the quarterfinals, she and Azarenka defeated top seeds Babos and Mladenovic, Barty's opponents in the 2018 final. They made the final, but lost in straight sets to Elise Mertens and Sabalenka. Although they only played eight tournaments during the season, they nearly qualified for the WTA Finals, falling one spot short in ninth place. 2021–2022: Comeback, Grand Slam titles Singles: Wimbledon and Australian Open champion, 100 weeks at No. 1 After an 11-month hiatus due to the COVID-19 pandemic, Barty returned to the tennis courts at the Yarra Valley Classic, one of the three lead-up tournaments to the Australian Open, where she defeated Garbiñe Muguruza in two tight sets in the final. After this, Barty entered the Australian Open as the first seed in the draw for the second consecutive year and projected as one of the favourites to claim the title, but was knocked out by Karolína Muchová in the quarterfinals. Barty played her first tournament outside Australia in more than a year at the Miami Open, where she was the defending champion from 2019. She had to save a match point in her opening match, but then recorded her first top-10 wins of the year against Aryna Sabalenka and Elina Svitolina to reach her second Miami Open final in a row. Barty defended her title by defeating Bianca Andreescu in the final after Andreescu retired from the match. She became the first No. 1 seed to win the Miami Open since Serena Williams in 2015. This was also Barty's first time defending a title in singles. Barty began the European red clay swing with her debut at the Stuttgart Open, where she won her third title of the year, and continued her clay-court success by posting her best result at the Madrid Open, where she lost to Sabalenka in the final. However, she was forced to retire at both the Italian Open and the French Open due to injuries that prevented her from playing any lead-up grass-court tournaments and delayed her comeback until Wimbledon. There, Barty beat former world No. 1 and 2018 champion, Angelique Kerber, to reach the final, where she defeated