Question: Diego Schwartzmann won the annual finals tournament in 2014, but failed to qualify to defend it in 2015, at which sport?

full_context: Document 1: Diego Schwartzman: Diego Sebastián Schwartzman (] , ] ; born 16 August 1992) is an Argentine professional tennis player competing mainly on the ATP Tour. He has won one ATP singles title, and reached a career-high singles ranking of world No. 28 in 2017. He is a clay court specialist, and is noted for his "deadly" return game.
Document 2: Guillermo Vilas: Guillermo Vilas (] ; born 17 August 1952) is a retired professional tennis player from Argentina, N°1 of the Grand Prix tennis circuit's Season in 1974, 1975 and 1977, who won four majors, seven Grand Prix Super Series titles and 62 ATP titles. He was inducted into the International Tennis Hall of Fame in 1991. Known for his prolific match play, especially on clay, he became the second man to win more than 900 matches in the Open Era, and his number of match wins on clay are by far the most of the Era. His peak was the 1977 season during which he won two major titles (both on clay), had two long match win streaks of 46 all-surface and 53 on clay, and finished with an Open Era record of match wins. In 2005, Tennis magazine ranked him as the 15th-best male player of the preceding 40 years. He also popularized the between-the-legs tweener shot, also known as the "Gran Willy" in his honor.
Document 3: Juan Martín del Potro: Juan Martín del Potro (] , born 23 September 1988), also known as Delpo is an Argentinian professional tennis player who is currently ranked world No. 24 in men's singles by the Association of Tennis Professionals (ATP). His biggest achievement has been winning the 2009 US Open, defeating Rafael Nadal in the semifinal and 5-time defending champion Roger Federer in the final. He was the first to defeat both Federer and Nadal during the same major and was the only man outside the Big Four to win a major between the 2005 French Open and the 2013 US Open, a span of 35 tournaments. He is also the second Argentine and the fifth-youngest man to win the US Open in the Open Era. Other career highlights include winning the bronze medal in men's singles at the 2012 London Olympics and the silver medal at the 2016 Rio Olympics and being part of his country's successful Davis Cup team; but his career has also been hampered by a succession of wrist injuries.
Document 4: Albert Costa: Costa began playing tennis at the age of five. He first came to the tennis world's attention as an outstanding junior player. In 1993, he reached the French Open junior final and won the Orange Bowl. He turned professional later that year and quickly established a reputation as a strong clay court player. Spanish former player and commentator for Spanish television Andrés Gimeno used to call him "the man with two forehands", because he could hit with the same accuracy and strength both forehand and backhand. In 1994, he won two challenger series events and was named the ATP's Newcomer of the Year.
Document 5: 2014 Karshi Challenger – Singles: Teymuraz Gabashvili was the defending champion, but decided not to compete.
Document 6: 2016 Abierto Mexicano Telcel – Men's Doubles: Ivan Dodig and Marcelo Melo were the defending champions, but chose to compete in Dubai and São Paulo, respectively, instead.<br>
Document 7: Dominic Thiem: Dominic Thiem (] ; born 3 September 1993) is an Austrian professional tennis player who has an ATP high ranking of world No. 7 which he first achieved on 6 June 2016. He has won eight singles titles on the ATP Tour.
Document 8: 2012 ABN AMRO World Tennis Tournament – Doubles: Jürgen Melzer and Philipp Petzschner were the defending champions but Melzer decided not to participate.<br>
Document 9: 2014 Samarkand Challenger – Singles: Teymuraz Gabashvili was the defending champion but decided not to participate.
Document 10: 2017 ABN AMRO World Tennis Tournament – Doubles: Nicolas Mahut and Vasek Pospisil were the defending champions, but Pospisil chose not to participate this year. Mahut played alongside Pierre-Hugues Herbert, but lost in the semifinals to Ivan Dodig and Marcel Granollers.
Document 11: 2015 ATP Challenger Tour Finals – Singles: Diego Schwartzman was the defending champion, but did not qualify this year.<br>
Document 12: 2016 Fergana Challenger – Men's Singles: Teymuraz Gabashvili was the defending champion, but decided not to defend his title.
Document 13: Sergio Roitman: Sergio Andres Roitman (born 16 May 1979) in Buenos Aires, Argentina, nicknamed 'Escopeta' ("Shotgun" in Spanish) is a retired professional tennis player from Argentina.
Document 14: Juan Mónaco: Juan Mónaco (] ; born 29 March 1984), nicknamed "Pico", is a male former tennis player from Argentina. He won nine singles titles, reached the semifinals of the 2010 Shanghai Masters and the 2012 Miami Masters, and achieved a career-high singles ranking of world no. 10 in July 2012. He announced his retirement from professional tennis on 15th May, 2017.
Document 15: 2016 Karshi Challenger – Singles: Teymuraz Gabashvili was the defending champion but chose not to participate.
ground_truth: tennis