Michaël Llodra and Fabrice Santoro were the defending champions, but had different outcomes.
 While Llodra did not compete this year, Santoro partnered with Nenad Zimonjić and reached the Quarterfinals, before losing to Jonas Björkman and Max Mirnyi.
Leander Paes and Nenad Zimonjić were the defending champions, but they did not participate together this year.
 Paes partnered Martin Damm, losing in the second round.
 Zimonjić partnered Max Mirnyi, losing in the second round.
The 2011 ATP World Tour Finals (also known as the 2011 Barclays ATP World Tour Finals for sponsorship reasons) was a tennis tournament that was played at the O Arena in London, United Kingdom between 20 and 27 November 2011.
 The defending champion in singles was world no. 4 Roger Federer, while the defending champions in doubles were Daniel Nestor and Nenad Zimonjić.
 However, they did not defend their title together as they separated after the 2010 event.
 Zimonjic formed a team with Michaël Llodra for the season, and Nestor partnered with Max Mirnyi.
 Federer successfully defended his crown, winning an unprecedented sixth title, while Nestor and Mirnyi captured the doubles title.
Daniel Nestor and Nenad Zimonjić were the defending champions, but they split in 2011.
 Daniel Nestor qualified with his new partner Max Mirnyi and Nenad Zimonjić with Michaël Llodra.
Max Mirnyi and Nenad Zimonjić were the defending champions, but did not participate together this year.
 Mirnyi partnered Mark Knowles, losing in the semifinals.
 Zimonjić partnered Brian MacPhie and successfully defended his title.
Daniel Nestor and Nenad Zimonjić were the defending champions and won in the final after the retirement of Mahesh Bhupathi and Max Mirnyi (while leading 6–3, 2–0).
Maksim "Max" Mirnyi (Belarusian: Максім Мікалаевіч Мірны ] ) (Russian: Максим Николаевич Мирный ] ) (born 6 July 1977, in Minsk) is a Belarusian professional tennis player.
Nenad Zimonjić (Serbian Cyrillic: , ] ; born June 4, 1976) is a Serbian professional tennis player who was ranked World No. 1 in 2008 in doubles.
 He is the second tennis doubles player from Serbia to hold the World No. 1, after Slobodan Živojinović.
 While Zimonjić is known as a doubles specialist (winning 3 Grand Slams in men's doubles and 5 in mixed doubles), he has recorded two big wins in his singles career.
 A 22 year span consisting of 54 Davis Cup ties including 43 victories has resulted in him becoming the most accomplished Davis Cup player in his nations history.
 His strongest weapon is very powerful first serve that he can hit at up to 235 km/h (146 mph).
Jonas Björkman and Max Mirnyi were the defending champions, but lost in quarterfinals to Fabrice Santoro and Nenad Zimonjić.
Daniel Nestor and Nenad Zimonjić were the defending champions, but decided not to participate together.
 Nestor partnered Max Mirnyi, while Zimonjić teamed up with Michaël Llodra.
 Mirnyi and Nestor defeated Zimonjić and Llodra in the semifinals, 7–6, 7–6.
 In the final, they won against Juan Sebastián Cabal and Eduardo Schwank 7–6, 3–6, 6–4 for their first Grand Slam doubles title as a team.

Question: Who was born earlier, Nenad Zimonjić or Max Mirnyi?
Answer: Nenad Zimonjić