With three Grand Slam and five Masters titles, the world number one ranking, a 70-6 win-loss record and a record prize money haul of USD 12.6 million, Serb Novak Djokovic was arguably the king of tennis in 2011.

He had been unbeaten in 43 matches in the first half of the season, dating back to the Davis Cup final in Dec 2010, until the run ended against 16-time Grand Slam champion Roger Federer in the French Open semifinals.

The streak brought him the second Australian Open title and all the season's opening four Masters at Indian Wells, Miami, Madrid and Rome, defeating Rafael Nadal in the finals of all of them.

The loss to Federer at the French Open did not dent Djokovic's self-belief and after taking a brief break, he went back on the winning track.

The Serb defeated Nadal to win the Wimbledon and ended the Roger-Rafa duopoly at the All England Club of the past eight years. In the process, Djokovic also took the Spaniard's world number one spot.

In the US Open final, Djokovic destroyed Nadal again after he had rallied past Federer from two sets, and two match points down, in a breathtaking semifinal.

Djokovic, who had ended each season ranked No.3 in the world behind Federer and Nadal for four long years, admitted that at times he was "a little bit" frustrated when Federer and Nadal were at the top of men's professional tennis, but soon realised that it was all part of a learning process as a sportsman.

"They have been the two most dominant players in the world the last five years. They have won most of the majors we are playing. So, sometimes it did feel a little bit frustrating when you kind of get to the latter stages of a Grand Slam. They always come up with their best tennis when it matters the most," Djokovic was quoted as saying by Xinhua.