Viswanathan Anand overcame Veselin Topalov's "homecourt advantage," retaining the World Chess Champion title by defeating the Bulgarian challenger 6.5-5.5 in a match held in Sofia, Bulgaria. In 2008, Anand completed the reunification of the World Chess Championship title that had been split up since 1993's boxing-style rupture in chess' organizational structure. I stand by my contention from two years ago that Anand has not joined Fischer or Kasparov at the very top level in chess' all-time pantheon but Anand has certainly traversed a unique and daunting path en route to becoming World Champion and holding on to that prestigious title; borrowing tennis terminology, he has "won on more surfaces" than any of the preceding champions:
1) Anand won a knockout style World Championship event sponsored by FIDE in 2000, holding that crown for two years.
2) Anand won a double round robin World Championship event sponsored by FIDE in 2007.
3) Anand defeated "Classical World Chess Champion" Vladimir Kramnik--who won his title by defeating Garry Kasparov in a match in 2000--6.5-4.5 in a 2008 match.
4) Anand successfully defended the unified title with his victory over Topalov, who won the double round robin 2005 FIDE World Championship tournament (ahead of Anand, among others) and was the highest ranked player in the world as recently as November, 2009. Topalov is currently second on the FIDE rating list--one point behind Norwegian prodigy Magnus Carlsen--while Kramnik is third on the list and Anand is fourth on the list (those ratings do not include the results of the Anand-Topalov match).
Each of those formats and all of his opponents presented unique challenges.
During an an interview conducted shortly after the match with Topalov ended, Anand provided some insights about the mentality that is required to win such a competition, stating, "It's just a question of nerves." In this high tech, computer dominated era, elite chess players prepare their opening moves to a greater and deeper extent than at any time in chess history but during the games they are under great pressure to remember this preparation while also being ready for any possible surprises (known as theoretical novelties) that their opponents might unleash. Topalov won the first game of the match when Anand got confused about the correct order of his prepared moves, an error which gave Topalov a crushing attack against Anand's exposed king--but Anand showed great psychological resilience by striking back with a game two win to level the score. Anand faced another potential crisis after his blunder in game eight transformed a drawn position into a loss but he steadied himself with three straight draws, setting up a climactic game 12 showdown; if the players drew then they would decide the title by contesting a playoff match consisting of rapid games but Topalov declined a possible draw and tried to finish Anand off at once, a decision that Topalov later admitted was influenced by the fact that Anand performs much better at rapid time controls than Topalov does. Topalov's attack backfired and Anand soon had a decisive advantage.