Mattek-Sands has won five singles and three doubles titles on the ITF Women's Circuit, and her best results in singles on the WTA Tour are reaching the fourth round of two Grand Slam events (Wimbledon in 2008 and the French Open in 2013), the semifinals of the tournaments in Cincinnati in 2005 and Birmingham in 2008, and the final of the Bell Challenge in 2008 and 2010. She reached a career-high singles ranking of No. 30 in the world on July 11, 2011. In women's doubles, Mattek-Sands has won 27 WTA Tour titles, including five Grand Slams at the 2015 Australian Open, 2015 French Open, 2016 US Open, 2017 Australian Open and 2017 French Open, all with Czech partner Lucie Šafářová. The pair also were the runners-up of the 2016 WTA Finals. She became the world No. 1 in doubles on January 9, 2017 and held the top ranking for a period of 32 consecutive weeks.