Mirjana Lučić-Baroni (; ; born 9 March 1982) is a Croatian former professional tennis player. She enjoyed a meteoric rise on the WTA Tour in the late 1990s, during which she set several "youngest-ever" records. She captured the women's doubles title at the 1998 Australian Open when she was 15 years old, partnered with Martina Hingis. She also won the first ever professional tournament she entered, the 1997 Croatian Ladies Open, and defended it the following year at age 16, making her the youngest player in history to successfully defend a title. She then reached the semifinals of the 1999 Wimbledon Championships, beating world No. 4, Monica Seles, and eighth seed Nathalie Tauziat, the previous year's finalist, before she lost to Steffi Graf in three sets. Following a series of personal problems from 2000 onwards, she faded from the scene. After toiling on the ITF Women's Circuit through much of the next decade, Lučić re-emerged as a WTA regular following the 2010 season. In September 2014, she upset world No. 2 Simona Halep in the third round of the US Open. The following week, she beat Venus Williams at the Tournoi de Québec final to claim the title, which set the record for the longest gap between titles in the Open Era. In January 2017, almost 18 years after her first Grand Slam semifinal, Lučić-Baroni reached the semifinals of the Australian Open, upsetting two top-5-ranked players before losing to Serena Williams. Three months later, she entered the singles rankings' top 20 for the first time in her career. Lučić-Baroni has been inactive since January 2018 due to a shoulder injury. Career Junior success Lučić began playing tennis at age 4 by hiding in the car when her older sister went to tennis classes and then sneaking into the lessons herself. As a junior player, she won the girls' singles title at the US Open in 1996, and singles and doubles crowns at the Australian Open in 1997, becoming the third player in the open era to win two junior Grand Slam singles titles before her 15th birthday (others being Martina Hingis and Jennifer Capriati). 1997–98: Grand Slam title Lučić turned professional in April 1997 at the age of 15. One week after turning pro, she won the first WTA Tour event she played in at Bol. She then reached the final of her second career event in Strasbourg, where she