Katarina Srebotnik (born 12 March 1981) is a Slovenian retired professional tennis player. She reached her career-high singles ranking of world No. 20 on 7 August 2006. On 4 July 2011, she reached No. 1 of the WTA doubles rankings, holding this ranking for 10 weeks. Srebotnik won four singles titles on the WTA Tour and was ranked inside the top 30 for several years. However, her best results have been on the doubles circuit, where she has won 39 WTA titles, including one Grand Slam title, at the 2011 Wimbledon Championships alongside Květa Peschke. She has also won five Grand Slam titles in mixed doubles, at the French Open in 1999, 2006 and 2010, the US Open in 2003 and the Australian Open in 2011. Career As a junior, she won the 1998 Wimbledon singles title and was runner-up at the US Open. Srebotnik was ranked No. 2 in the junior rankings in 1997 and 1998. She was mentored by Gabriela Sabatini. 1995–1999: WTA Tour debut and historic Guinness World record Srebotnik made her debut on the ITF Women's Circuit in 1995, winning the singles tournaments in Ismailia in 1996, Zadar in 1997 and Šibenik in 1998. In 1998, Srebotnik won the doubles title on her WTA Tour debut at the Makarska Open (with Tina Križan), and later that year reached the doubles final at the Austrian Open, also with Tina Križan. In 1999, her win at the ITF tournament in Dubai gave her direct entry into her first tour-level singles event in Estoril, where she became the fourth player to win on her tour debut, defeating Rita Kuti-Kis in the final. She broke into the top 100 on April 12, 1999 at No. 88. In May 1999, Srebotnik played in her first Grand Slam singles main draw at Roland Garros, losing to Arantxa Sánchez Vicario in the second round. She won her first Grand Slam title in the mixed doubles with Piet Norval, becoming the first woman ever to win her first tour event in singles, doubles and mixed doubles. Only Mirjana Lučić had previously won on debut in both singles and doubles. 2000–2004 Srebotnik reached her first Tier-I semifinal in Tokyo at the Pan Pacific Open, which she lost to Sandrine Testud. On 7 February 2000, Srebotnik broke into the top 50 at No. 49. She won her fourth career doubles title at Estoril (with Tina Križan).