[2] Stosur was also the top-ranked Australian singles player for 452 consecutive weeks, from October 2008 to June 2017, and was ranked inside the top 25 for a period of nine straight years.

After the French Open, Stosur started showing symptoms of what was months later diagnosed as Lyme disease, an infection transmitted by bite of ticks.

Stosur showed great promise at Wimbledon: while only making the second round in singles, losing to Nicole Vaidišová, she made the finals of both the ladies' and mixed doubles.

The Australian team, which also included Casey Dellacqua and Jelena Dokić, advanced to the World Group II play-offs, winning all of its twelve rubbers.

Having beaten Black and Huber in the semifinals, she was a runner-up in the doubles tournament, losing the final to Ai Sugiyama and Akgul Amanmuradova with Stubbs.

On the US Open Series in Stanford, Stosur made it into the semifinals after defeating sixth seed Dominika Cibulková, Monica Niculescu and causing a massive upset win over Serena Williams.

At the same tournament, Stosur and Stubbs defeated Black and Huber in the semifinals but lost to Nuria Llagostera Vives and María José Martínez Sánchez in the final.

She then travelled to Adelaide to represent Australia at the Fed Cup alongside Alicia Molik, Casey Dellacqua and Rennae Stubbs against Spain.

Coming into the French Open, Stosur was seeded seventh and was one of the favourites to win the title, due to her semifinal run in 2009 and her tour-best 14–2 record on clay in 2010.

After taking time off to recover from her injury, she took part in the Pilot Pen Tennis tournament at New Haven, in hopes of regaining some of the lost ranking points and in preparation for the US Open.

Instead, she competed at the final Premier Mandatory event of the year, the China Open, where she lost in the first round to qualifier Anastasija Sevastova in three sets.

In Stuttgart, as fifth seed, Stosur lost to Julia Görges in the semifinals, but she won in the doubles tournament, partnering Sabine Lisicki, by defeating the German team of Kristina Barrois and Jasmin Wöhr in the final.

Stosur began her US Open Series campaign with a straight-set loss to her doubles partner, Lisicki, in the second round of Bank of the West Classic.

Stosur then traveled to the United States to compete in the Indian Wells Open, where she defeated young American Irina Falconi, to make the third round, where she lost a very tough match to Nadia Petrova.

Defending a Grand Slam title for the first time, Stosur comfortably made it through the first three rounds at the US Open against Petra Martić, Edina Gallovits-Hall, and 31st seed Varvara Lepchenko.

[31] Stosur bounced back from a poor start to the season to win her second-round match at the Qatar Ladies Open over Monica Niculescu in three sets.

[48] Following the disappointing loss in Madrid, Stosur moved on to the Italian Open and rebounded with her first win of the European clay season on her third attempt, comfortably defeating Hsieh Su-wei.

[56][57] At Wimbledon, she reached the third round for only the second time in her career, after defeating lucky loser Anna Karolína Schmiedlová and Olga Puchkova both in straight sets.

[77] Stosur moved on to play Eugenie Bouchard in the final, taking 2 hours and 13 minutes to capture her fifth career title, coming from a set down to win.

At the end of the season, Stosur parted company with her coach David Taylor and employed Miles Maclagan who had previously worked with Andy Murray and Laura Robson.

Stosur then received a walkover against Lesia Tsurenko and defeated fellow Aussie Ajla Tomljanović and Sloane Stephens to reach her first final of 2015.

In the final, she faced Kristina Mladenovic and came from a set down to record a victory, and win her seventh title on the WTA Tour, her first on red clay.

Stosur then started her hardcourt season in Washington where she reached the semifinals after defeating Mladenovic, Falconi and Niculescu before losing to eventual champion Sloane Stephens.

In the North American hardcourt swing, Stosur reached the last 16 in Indian Wells, after three-set wins over Yanina Wickmayer and Christina McHale.

Partnering with Daria Gavrilova in the women's doubles, the duo lost to fifth seeded Swiss pairing of Timea Bacsinszky and Martina Hingis the eventual silver medallist in opening round.

In mixed doubles, Stosur paired up with John Peers and lost to the fourth seeds Sania Mirza and Rohan Bopanna in the first round.

Entering the US Open as the 16th seed, Stosur won her first-round match against Italian Camila Giorgi in a three-set thriller, before losing to Zhang Shuai in straight sets in the second round.

She defeated Latvian Anastasija Sevastova and eighth seed Barbora Strýcová before falling to Dominika Cibulková in straight sets for the first time.

In Madrid, Stosur lost in the third round to the fourth seed Simona Halep, having defeated Sara Sorribes Tormo and Mariana Duque Mariño.

[citation needed] Stosur then received a wildcard for her final singles tournament, the 2022 Internationaux de Strasbourg, where she lost in the first round to Harmony Tan.