Question: Which tennis player is younger, Sun Tiantian or Anna Kournikova?

full_context: Document 1: Martina Hingis: Martina Hingis (born 30 September 1980) is a Swiss professional tennis player, a former world No. 1 singles player and currently ranked world No. 2 in doubles by the WTA. She has spent a total of 209 weeks as the singles No. 1 and has won five Grand Slam singles titles, thirteen Grand Slam women's doubles titles, winning a calendar-year doubles Grand Slam in 1998, and seven Grand Slam mixed doubles titles; for a combined total of twenty-five major titles. In addition, she has won the season-ending WTA Championships two times in singles and three times in doubles, and an Olympic silver medal.
Document 2: Hsieh Su-wei: Hsieh Su-wei (born January 4, 1986) is a professional female tennis player from Taiwan. s of 25 2013 she was ranked No. 23 in the WTA Tour singles rankings and is the highest-ranked Taiwanese women's singles player ever. Currently she is the top-ranked WTA player from Taiwan in both singles and doubles.
Document 3: Anastasia Myskina: Anastasiya Andreyevna Myskina (Russian: Анастасия Андреевна Мыскина ; ] ; born 8 July 1981) is a Russian former tennis player. She won the 2004 French Open singles title, becoming the first Russian female tennis player to win a Grand Slam singles title. Subsequent to this victory, she rose to No. 3 in the WTA rankings, becoming the first Russian female tennis player to reach the top 3 in the history of the rankings. In September 2004, she reached a career-high ranking of No. 2. She has not officially retired, but has been inactive on the WTA Tour since May 2007.
Document 4: Anna Kournikova (computer virus): Anna Kournikova (named by its author as "Vbs.OnTheFly Created By OnTheFly") was a computer worm written by a 20-year-old Dutch student named Jan de Wit --who called himself 'OnTheFly'-- on February 11, 2001. It was designed to trick email users into opening a mail message purportedly containing a picture of the tennis player Anna Kournikova, while actually hiding a malicious program. The worm arrives in an email with the subject line "Here you have, ;0)" and an attached file called AnnaKournikova.jpg.vbs. When launched under Microsoft Windows the file does not display a picture of Anna Kournikova but launches a viral Visual Basic Script that forwards itself to everybody in the Microsoft Outlook address book of the victim.
Document 5: Svetlana Kuznetsova: Svetlana Aleksandrovna Kuznetsova (Russian: Светла́на Алекса́ндровна Кузнецо́ва ; ] ; born 27 June 1985) is a Russian tennis player. Kuznetsova has appeared in four Grand Slam singles finals, winning two, and has also appeared in seven doubles finals, winning twice. As a doubles player, Kuznetsova has reached the finals of each Grand Slam at least once, winning the Australian Open twice. She is currently the No. 8 ranked player on the WTA rankings.
Document 6: Sania Mirza: Sania Mirza (] ; born 15 November 1986) is an Indian professional tennis player who was formerly ranked No. 1 in the women's doubles rankings. From 2003 until her retirement from singles in 2013, she was ranked by the Women's Tennis Association as India's No. 1 player, both in singles and doubles. Throughout her career, Mirza has established herself as the most successful female Indian tennis player ever and one of the highest-paid and high-profile athletes in the country.
Document 7: Peng Shuai: Peng Shuai (; ; born 8 January 1986) is a Chinese professional female tennis player. She reached a career high ranking of World No. 1 in doubles by the Women's Tennis Association on 17 February 2014, making her the first Chinese professional tennis player (male or female, and in singles or doubles) to reach World No. 1. She won a gold medal at the 2010 Asian Games, defeating Akgul Amanmuradova in the final. At the 2013 Wimbledon Championships, Peng won her first ladies' double championship with Hsieh Su-wei of Taiwan and again won at the 2014 French Open with Hsieh.
Document 8: Ana Ivanovic: Ana Ivanovic (Serbian: Ана Ивановић, "Ana Ivanović" ; ] ; born 6 November 1987) is a retired Serbian tennis player. She was ranked No. 1 in the world in 2008, after she had defeated Dinara Safina to win the 2008 French Open. She was also the runner-up at the 2007 French Open and the 2008 Australian Open. She also qualified for the annual WTA Tour Championships three times, in 2007, 2008 and 2014 and won the year-end WTA Tournament of Champions twice, in 2010 and 2011.
Document 9: Evgeny Korolev: Evgeny Evgenyevich Korolev (Russian: Евге́ний Евге́ньевич Королёв ; born 14 February 1988) is Kazakhstani tennis player and the cousin of former Russian player Anna Kournikova. He began playing tennis at age four with his father, and picked up his first ATP points at age 15 in three German challenger events. He can speak Russian, German, English and Spanish.
Document 10: 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 11: Maria Sharapova: Maria Yuryevna Sharapova (Russian: Мари́я Ю́рьевна Шара́пова ; ] ; born April 19, 1987) is a Russian professional tennis player. A United States resident since 1994, Sharapova has competed on the WTA tour since 2001. She has been ranked world No. 1 in singles by the WTA on five separate occasions, for a total of 21 weeks. She is one of ten women, and the only Russian, to hold the career Grand Slam. She is also an Olympic medalist, having earned silver for Russia in women's singles at the 2012 Summer Olympics in London.
Document 12: Sun Tiantian: Sun Tiantian (; ; born 12 October 1981) is a Chinese former professional tennis player.
Document 13: Jennifer Capriati: Jennifer Maria Capriati (born March 29, 1976) is an American former professional tennis player. A member of the International Tennis Hall of Fame, she won three singles championships in Grand Slam tournaments and a gold medal at the 1992 Summer Olympics in Barcelona, reached the World No. 1 ranking, and is considered one of the greatest tennis players of all time.
Document 14: Li Na career statistics: This is a list of the main career statistics of Chinese professional tennis player, Li Na. Over the course of her career, Li won nine WTA singles titles, including two Grand Slam singles titles at the 2011 French Open and 2014 Australian Open and one WTA Premier 5 singles title at the 2012 Western & Southern Open. She also finished in fourth place at the 2008 Beijing Olympics and was the runner-up at the 2011 and 2013 Australian Open and 2013 WTA Tour Championships. Li achieved a career high singles ranking of World No. 2 on February 17, 2014.
Document 15: 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.
ground_truth: Sun Tiantian