"I managed to have the best year of my career in 2011 and I knew that it was going to be difficult in 2012 to maintain No. 1 in the world and play consistently," Djokovic said.
"I did, and so this year was an even more successful year from a psychological aspect. ... Ambitions are always high and I want to win every Grand Slam and major tournament I play and this year is no different."
