London: World No.1 Novak Djokovic believes it was not improvements to his game but his mentality that helped him win three Grand Slam titles in 2011.

Reflecting on a hugely successful season, Djokovic believes it was his new-found maturity which made the difference.

"It's true that I have improved but by a very small percentage," Djokovic told a sports channel.

"It's the same game I've had the last couple of years. It's my mental approach on the court that's changed."

"That was the difference. I stepped it up. I matured and said, 'It's my time. I can do it. I can win major titles'. I think luck falls on not just the brave but also the ones who believe they belong there."

After a brief break, Djokovic will return to action next month, when one of his first tasks will be to defend his Australian Open title - the first of 10 title defences in 2012. But Djokovic already has his sights on another prestigious title on the Wimbledon courts in 2012.

"I'm only 24, and I want to have many more successful years, win as many major titles as possible," Djokovic said. "The Olympics are coming up. I want a medal."