Question: Which tennis player Anna-Lena Grönefeld or Mats Wilander turned professional first ?
Context: The 2012 US Open Men's Singles final was the championship tennis match of the Men's Singles tournament at the 2012 US Open.  In the final, Andy Murray defeated defending champion Novak Djokovic 7–6, 7–5, 2–6, 3–6, 6–2 to win the match.  It was the equal-longest US Open men's final in history, lasting 4 hours and 54 minutes (equalling the 1988 US Open final played by Ivan Lendl and Mats Wilander), and the equal second-longest men's final in the Open era, only behind the 2012 Australian Open final.  By winning the 2012 US Open, Murray became the first British man since Fred Perry in 1936 to win a Grand Slam singles title, and the first British man in the Open Era to do so.  The match is a significant part of the rivalry between the two players.  This match also marked a milestone for Murray, as it was his 100th match win at a grand slam tournament. The 2012 Australian Open Men's Singles final was the championship tennis match of the Men's Singles tournament at the 2012 Australian Open between two of the best players of their generation.  In the final, Novak Djokovic defeated Rafael Nadal 5–7, 6–4, 6–2, 6–7, 7–5 to win the tournament.  It was the Grand Slam final match with the longest duration in history, lasting 5 hours 53 minutes, overtaking the record previously set by the 1988 US Open Final between Mats Wilander and Ivan Lendl.  The match is considered to be one of the best matches in modern tennis.  With both players playing at their highest levels, the match is memorable for being a war of attrition and for the impeccable quality and duration of play between Djokovic and Nadal.  Before this final, Novak Djokovic played his semifinal match against Andy Murray in a match lasting 4 hours and 50 minutes. Jean-Julien Rojer (] ; born 25 August 1981) is a Dutch professional tennis player from Curaçao.  His highest ATP singles ranking is 218th, which he achieved on 15 August 2005.  A doubles specialist, his career-high in doubles is World No. 3, which he reached in November 2015.  His former doubles partners include Eric Butorac and Aisam-ul-Haq Qureshi.  He currently plays with Horia Tecău of Romania, with whom he won the men's double titles in the 2015 Wimbledon and 2017 US Open championships.  With Anna-Lena Grönefeld, he also won the mixed doubles' title at the 2014 French Open.  He attended UCLA where he competed for the UCLA Bruins men's tennis team. Ramesh Krishnan (Tamil: ரமேஷ் கிருஷ்ணன் ) (born 5 June 1961) is a tennis coach and former professional tennis player from India.  As a junior player in the late 1970s, he won the boys' singles titles at both Wimbledon and the French Open.  He went on to reach three Grand Slam quarter-finals in the 1980s and was a part of the Indian team which reached the final of the Davis Cup in 1987.  Krishnan also beat then World No. 1, Mats Wilander, at the 1989 Australian Open.  He became India's Davis Cup captain in 2007. Anna-Lena Grönefeld (born 4 June 1985) is a German tennis player.  She turned professional in April 2003. Roger Federer won three Grand Slams in 2004 for the first time in his career.  The first came at the Australian Open over Marat Safin, 7–6(3), 6–4, 6–2.  He went on to win his second Wimbledon crown over Andy Roddick, 4–6, 7–5, 7–6(3), 6–4.  In addition, Federer defeated the 2001 US Open Champion Lleyton Hewitt at the US Open for his first US Open title, 6–0, 7–6(3), 6–0.  Furthermore, Federer won three ATP Masters 1000 events, one on clay at Hamburg, and two on hard court in Indian Wells and Canada.  Federer took the ATP 500 series event at Dubai, and wrapped up the year for the second time over Lleyton Hewitt at the Tennis Masters Cup.  Federer was the first player to win three Grand Slams in a single season since Mats Wilander in 1988. 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. Maria Yuryevna Kirilenko-Stepanova (Russian: Мари́я Ю́рьевна Кириле́нко ; ] ; born 25 January 1987) is a Russian tennis player.  Kirilenko won the 2002 U.S. Open Girls' Singles and won her first WTA Tour title in 2005, defeating Anna-Lena Grönefeld in the China Open.  She has reached three Grand Slam singles quarterfinals, at the 2010 Australian Open the 2012 Wimbledon Championships and the 2013 French Open.  In doubles, she has reached two Grand Slam doubles finals, at the 2011 Australian Open and the 2012 French Open, won the 2012 WTA Tour Championships and was a bronze medalist at the 2012 London Olympics.  In June 2013, Kirilenko reached her career high ranking of World No. 10. 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). This is a list of the main career statistics of Swedish former professional tennis player Mats Wilander whose career ran from 1980 until 1996.
Answer: Mats Wilander