Question: Which tennis player Anna-Lena Grönefeld or Mats Wilander turned professional first ?

full_context: Document 1: Anna-Lena Grönefeld: Anna-Lena Grönefeld (born 4 June 1985) is a German tennis player. She turned professional in April 2003.
Document 2: Laura Siegemund: Laura Natalie Siegemund (born 4 March 1988 in Filderstadt) is a German professional tennis player.
Document 3: Elena Likhovtseva: Elena Alexandrovna Likhovtseva (Russian: Елена Александровна Лиховцева ] ; born 8 September 1975) is a Russian former tennis player. She turned professional in January 1992 at the age of 16.
Document 4: 1981 US Open – Men's Singles: John McEnroe was the two time defending champion and retained his title again, defeating Björn Borg 4–6, 6–2, 6–4, 6–3 in the final to win the Men's Singles tennis title at the 1981 US Open in a repeat of the previous years final, and which turned out to be Borg's final grand slam match.
Document 5: Li Na: Li Na (; ; born 26 February 1982) is a retired Chinese professional tennis player, who achieved a career-high WTA-ranking of world No. 2 on 17 February 2014. Over the course of her career, Li won seven WTA singles titles and two Grand Slam singles titles at the 2011 French Open and 2014 Australian Open. Li's rise to prominence came after those victories, which made her the first and only Grand Slam singles champion from East Asia and Asia as a whole. Prior to this, she had already become the first player representing an East Asian and Asian country to appear in a Grand Slam singles final, a milestone she achieved at the 2011 Australian Open. Li was also the runner-up at the 2013 Australian Open and 2013 WTA Tour Championships, a three-time quarterfinalist at Wimbledon and a semifinalist at the 2008 Beijing Olympic Games and 2013 US Open. Among her other most notable accolades, she was the first Chinese player to win a WTA tour title at the Guangzhou International Women's Open in 2004, the first to reach a Grand Slam singles quarterfinal at the 2006 Wimbledon Championships, and the first to break into the world's top 10. Her feats have sparked a major population growth of tennis players in East Asia, earning her the reputation as the region's tennis pioneer and trailblazer.
Document 6: 1982 Swedish Open: The 1982 Swedish Open was a men's professional tennis tournament played on outdoor clay courts and held in Båstad, Sweden. It was part of the 1982 Grand Prix circuit. It was the 35th edition of the tournament and was held from July 12 through July 19, 1982. Mats Wilander won the singles title.
Document 7: 1987 US Open – Men's Singles: Ivan Lendl was the two time defending champion and retained his title again, defeating Mats Wilander 6–7, 6–0, 7–6, 6–4 in the final to win the Men's Singles tennis title at the 1987 US Open. It was also the 6th consecutive US Open final of Lendl's record 8 consecutive US Open finals.
Document 8: Anna Kournikova: Anna Sergeyevna Kournikova (Russian: А́нна Серге́евна Ку́рникова ; ] ; born 7 June 1981) is a Russian former professional tennis player. Her appearance and celebrity status made her one of the best known tennis stars worldwide. At the peak of her fame, fans looking for images of Kournikova made her name one of the most common search strings on Google Search.
Document 9: Steffi Graf: Stefanie Maria "Steffi" Graf (] ; born 14 June 1969) is a German former tennis player, who was ranked world No. 1 during her career. Graf won 22 Grand Slam singles titles. Her 22 singles titles put her second on the list of Major wins in the female competition since the introduction of the Open Era in 1968 and is third all-time behind Margaret Court (24) and Serena Williams (23). In 1988, she became the first and only tennis player (male or female) to achieve the Golden Slam by winning all four Grand Slam singles titles and the Olympic gold medal in the same calendar year. Furthermore, she is the only tennis player to have won each Grand Slam event at least four times.
Document 10: 1988 US Open – Men's Singles: Mats Wilander defeated three time defending champion Ivan Lendl, 6–4, 4–6, 6–3, 5–7, 6–4 in the final to win the Men's Singles title at the 1988 US Open. This was the longest US Open men's final in history, clocking in at four hours and fifty-four minutes; this record was matched in 2012 when Andy Murray defeated Novak Djokovic in that year's final.
Document 11: Mats Wilander: Mats Wilander (] ; born 22 August 1964) is a former World No. 1 tennis player from Sweden. From 1982 to 1988, he won seven Grand Slam singles titles (three at the French Open, three at the Australian Open, and one at the US Open), and one Grand Slam men's doubles title (at Wimbledon).
Document 12: Mats Wilander career statistics: This is a list of the main career statistics of Swedish former professional tennis player Mats Wilander whose career ran from 1980 until 1996.
Document 13: Angelique Kerber: Angelique Kerber (] ; born 18 January 1988) is a German professional tennis player and former world No. 1. Having made her professional debut in 2003, Kerber rose to prominence upon reaching the semifinals of the 2011 US Open as the no. 92 ranked player in the world. She ascended to the top of the rankings on 12 September 2016, thus becoming the twenty-second and oldest player to achieve the number one ranking for the first time and the first new number one player since Victoria Azarenka in 2012.
Document 14: Hana Mandlíková: Hana Mandlíková (born 19 February 1962) is a former professional tennis player from Czechoslovakia who later obtained Australian citizenship. During her career, she won four Grand Slam singles titles: the 1980 Australian Open, 1981 French Open, 1985 US Open, and the 1987 Australian Open. She was also the runner-up at four Grand Slam singles events, including the Wimbledon finals of 1981 and 1986, and won one Grand Slam women's doubles title, the 1989 US Open with Martina Navratilova.
Document 15: Stefan Edberg: Stefan Bengt Edberg (] ; born 19 January 1966) is a Swedish former world no. 1 professional tennis player (in both singles and doubles). A major proponent of the serve-and-volley style of tennis, he won six Grand Slam singles titles and three Grand Slam men's doubles titles between 1985 and 1996. He also won the Masters Grand Prix and was a part of the Swedish Davis Cup-winning-team four times. In addition he won four Masters Series titles, four Championship Series titles and the unofficial Olympic tournament 1984, was ranked in the singles top 10 for ten successive years, 9 years in the top 5, and is considered one of the greatest players of his era. Edberg began coaching Roger Federer in January 2014, with this partnership ending in December 2015.
ground_truth: Mats Wilander