Question: What nationality was the defending champion at the 2007 Sunfeast Open – Singles ?

Context paragraphs:
Lucie Šafářová: Lucie Šafářová (] ; born 4 February 1987) is a Czech professional tennis player from Brno.  She is currently the WTA world No. 1 doubles player.  Šafářová has won seven WTA tour singles titles, fifteen doubles titles and reached the quarterfinals of the 2007 Australian Open by upsetting defending champion Amélie Mauresmo in the fourth round.  She reached her first Grand Slam semifinal at the 2014 Wimbledon Championships and her first Grand Slam final at the 2015 French Open.  She also won the 2015 Australian Open, 2015 French Open, 2016 US Open, 2017 Australian Open and 2017 French Open women's doubles titles partnering with Bethanie Mattek-Sands.

2012 BNP Paribas Open – Women's Singles: At the 2012 BNP Paribas Open – Women's Singles, played at Indian Wells, California in March 2012, the defending champion Caroline Wozniacki lost to Ana Ivanovic in the fourth round, the second consecutive year Ivanovic had knocked out the defending champion.  World No. 1 Victoria Azarenka won her first Indian Wells Title by beating World No. 2 Maria Sharapova 6–2 6–3 in the final.

2012 US Open – Men's singles final: 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.

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.

2007 Sunfeast Open – Singles: Martina Hingis was the defending champion, but chose not to participate that year.

2010 Roger Federer tennis season: Roger Federer won the Australian Open, beating Briton Andy Murray, whom he also beat in the final of the 2008 US Open.  Federer played in eighteen tournaments in 2010, and won five.  He made the semifinals of his opening tournament at the Qatar Open in Doha, losing to Nikolay Davydenko, and at the Estoril Open, which he had won in 2008, losing to defending and eventual champion Albert Montañés.  Federer was runner-up in the Mutua Madrileña Madrid Open to Rafael Nadal.  At the French Open, he faced his opponent in the previous year's final, Robin Söderling at the quarterfinals stage and lost.  As defending champion at Wimbledon, he was defeated in the quarterfinals by Tomáš Berdych in four sets, thus ending his streak of seven consecutive Wimbledon finals also falling to world no. 3, his lowest ranking since 2003.  During the summer hard-court season, Federer hired Paul Annacone to be his coach and revive his form.  At the 2010 US Open, Federer advanced to his seventh straight semifinal appearance, but lost to Novak Djokovic in five sets, despite holding two match points in the final set.  Federer's ranking slipped from no. 2 to no. 3 after the tournament, but he finished the year strong with victories in Stockholm, Basel, and the ATP Tour Finals to pass Djokovic in the rankings and finish the year at no. 2.

2007 Sunfeast Open: The 2007 Sunfeast Open was a Tier III tennis event on the 2007 WTA Tour, organised for women's professional tennis.  This was the third edition of the tournament.

Mariya Koryttseva: Koryttseva made a surprising run to the final of the 2007 Sunfeast Open, held in Kolkata, India, in September 2007.  En route to her appearance in the final, she beat Monique Adamczak, Vania King, who had defeated the number one seed Marion Bartoli in the previous round, Tatiana Poutchek and Anne Keothavong.  Her run came to an end at the hands of Maria Kirilenko, who beat her 6–0, 6–2 in the final.  She lost the doubles finals as well.

Neha Uberoi: Neha Uberoi (born 6 February 1986, in Morristown) is a retired Indian-American professional tennis player.On 29 January 2007, she reached her best singles ranking of world number 196.  On 22 May 2006, she peaked at world number 107 in the doubles rankings.  In doubles, she was a finalist at the 2005 Sunfeast Open and the 2005 Guangzhou International Women's Open.  Uberoi retirement from tennis 2010.

British Speedway Under 21 Championship: The British Speedway Under-21 Championship (also known as the British Junior Speedway Championship) is an annual speedway competition open to riders of British nationality aged at least fifteen on the date of the first meeting, and under twenty-one on 1 January in the year of the competition.  Sixteen riders plus three reserves take part in 20 heats with each rider facing each other once.  The two riders which accumulate the highest amount of points over the heats go straight to the final.  The next four highest point scorers take part in a race-off, with first and second place riders also progressing to the final.  The winner of the final is declared British Under-21 Champion.  Previous winners include former World Champions Mark Loram and Gary Havelock.  The 2009 championship was won by Lewis Bridger who defeated defending champion Tai Woffinden in the final.  Joe Haines was third and Ben Barker finished fourth.

Supporting paragraphs: 2007 Sunfeast Open – Singles Martina Hingis
Answer: Swiss