Samantha Jane Stosur (born 30 March 1984) is an Australian former professional tennis player. She was a world No. 1 in doubles, a ranking which she first achieved on 6 February 2006 and held for 61 consecutive weeks. Also a former top ten singles player, Stosur reached a career-high singles ranking of world No. 4 on 21 February 2011 and spent a total of 165 weeks ranked inside the top ten, between March 2010 and June 2013. 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. She won a combined total of 40 career titles (9 in singles, 28 in doubles, and 3 in mixed doubles), including eight major titles, and amassed more than $20 million in prize money.
Stosur won a major singles title at the 2011 US Open, where she beat Serena Williams in the final and became the first Australian woman since Evonne Goolagong Cawley in 1980 to win a Grand Slam tournament. She had previously reached another major singles final at the 2010 French Open, along the way defeating former world No. 1 and four-time champion Justine Henin in the fourth round, ending the Belgian's 24-match winning streak at the tournament, and then-world No. 1 Serena Williams in the quarterfinals, before losing to Francesca Schiavone. Her other major singles achievements include two semifinal finishes at the WTA Finals in 2010 and 2011, as well as reaching three WTA 1000 finals (the Italian Open and Canadian Open in 2011, and the Qatar Open in 2012) and the final of the WTA Elite Trophy in 2013. She also reached the semifinals of the French Open in 2009, 2012 and 2016, and the US Open quarterfinals in 2010 and 2012.
Stosur is a four-time major champion in women's doubles, winning the 2005 US Open and 2006 French Open with Lisa Raymond, and the 2019 Australian Open and 2021 US Open with Zhang Shuai, and reaching an additional five major finals (three with Raymond, one with compatriot Rennae Stubbs, and one with Sabine Lisicki). She won back-to-back WTA Tour Championships doubles titles with Raymond in 2005 and 2006, and was the co-year end world No. 1 with Raymond in 2006. Stosur has also won three mixed-doubles Grand Slam tournament titles, at the 2005 Australian Open with Scott Draper, the 2008 Wimbledon Championships with Bob Bryan, and the 2014 Wimbledon Championships with Nenad Zimonjić.
Stosur was born in Brisbane, Queensland and spent the first six years of her life living on the Gold Coast. She is the daughter of Tony and Diane, and has two brothers, Dominic and Daniel. The Stosur family is of Polish descent through Sam's paternal grandfather. When she was six, the family house and business on the Gold Coast were destroyed by a flood, and the family moved to Adelaide. There she started playing tennis, when she was given a racquet for Christmas at the age of eight. While her parents worked long hours at the cafe they had started, Stosur played at local courts with older brother Daniel, who later encouraged their parents to take her to tennis lessons. Her family returned to the Gold Coast when Stosur was eleven years of age. There she attended initially attended Robina State Primary School alongside close friend Nick Riewoldt and later switched to Helensvale State High School. She went away on her first overseas trip at the age of 13, competing in the World Youth Cup in Jakarta, Indonesia.
At the age of 14, Stosur joined the Queensland Academy of Sport (QAS) under Geoff Masters. In 2001, when she was 16, she joined the Australian Institute of Sport tennis program.
Stosur first played professional tennis in 1999 at the age of 15 at an ITF Women's Circuit event in her home state of Queensland where she claimed a straight sets first round victory in the qualifying draw before losing her second round qualifying match (2–6, 6–3, 3–6). In 2000, she debuted at the Australian Open losing in the first qualifying round. In the following year, she won four straight ITF titles. In 2002, she lost in the first round at the Gold Coast hardcourts event.
In 2003, Stosur won her first WTA Tour singles matches, reaching the third round of the Australian Open. She lost in the third round to No. 7 seed, Daniela Hantuchová. She also qualified for the WTA event in Memphis.
In 2004, Stosur reached the semifinals of the Gold Coast event, before falling to Ai Sugiyama. She reached the second round of the Hobart International, then the second round of the Australian Open, and later qualified for WTA events in Acapulco, Indian Wells, Vienna and Birmingham. Stosur competed at the Athens Olympics, where she lost in the first round. She continued to play WTA events, qualifying for the Japan Open and Bali in the autumn of 2004. At the end of the 2004 season, she reached the doubles final in Québec City, partnered with Els Callens from Belgium.
Stosur reached her first WTA Tour final at her home event in Gold Coast, losing to Patty Schnyder. She was runner-up at the Sydney event, defeating by walkover the world No. 1, Lindsay Davenport, in the quarter-final and Elena Dementieva in the semifinal, before losing to fellow Australian Alicia Molik, and won her first doubles title partnering Australian Bryanne Stewart at the same tournament. Stosur lost to world No. 2, Amélie Mauresmo, in the first round of the Australian Open, but won the mixed-doubles title with Scott Draper over Liezel Huber and Kevin Ullyett.
In July, she teamed up with American Lisa Raymond, winning seven WTA doubles titles before the end of the year, including the US Open, the Kremlin Cup and the WTA Championships. Stosur finished the year ranked No. 46 in singles and No. 2 in doubles.
In 2006, she represented Australia alongside Todd Reid at the Hopman Cup, winning all of her singles matches. She then lost in the first round in Sydney International to Nicole Vaidišová in three sets. At the Australian Open, Stosur made it to the fourth round in singles, falling to Martina Hingis. She and Lisa Raymond also made it to the doubles final, where they were defeated by Chinese duo Yan Zi and Zheng Jie.
After losing in Melbourne, Stosur and Raymond won 18 straight matches, winning titles in Tokyo, Memphis, Indian Wells and Miami. They also won in Charleston, at the French Open, and the WTA Championships. On 28 August, Stosur had a career-high ranking of No. 30, after reaching the semifinals at New Haven, where she lost to Lindsay Davenport in two tiebreakers. She finished off 2006 by winning the doubles title at the WTA Championships in Madrid, ranked No. 1 in doubles, and a career high to that point, No. 29 in singles.
Stosur and Raymond successfully defended their doubles titles in Tokyo, Indian Wells and Miami. The pair also won the German Open in Berlin. In singles, Stosur reached three quarter-finals, at Gold Coast, Tokyo and Memphis. At Rome, she defeated top-seed Amélie Mauresmo in the second round, saving two match points, before losing to Patty Schnyder in the following round.
After the French Open, Stosur started showing symptoms of what was months later diagnosed as Lyme disease, an infection transmitted by bite of ticks. By then, her form had slumped. She lost in the second round at Wimbledon, withdrew from many tournaments on the American hardcourt swing, and lost in the first round of the US Open, where she was seeded 29th, to No.-96-rated Alizé Cornet. Stosur did not play in any more tournaments in 2007.
She returned playing two ITF events before the Rome Masters in May, where she was defeated in the second round by Venus Williams. The tournament also saw the return of the doubles team of Stosur and Lisa Raymond with a second-round loss. Less than a month later, they were defeated in the third round of the French Open, where Stosur reached the second round in singles, losing to Petra Kvitová.
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. She and Raymond lost the final to Venus and Serena Williams. The Williams sisters had just played against each other in the final of the ladies singles. With mixed-doubles partner Bob Bryan, Stosur defeated Mike Bryan and Katarina Srebotnik to win the title.