Novak Djokovic highly motivated as he looks to reclaim top ranking

Novak Djokovic, entering a tournament as the second-ranked player for the first time since 2014, says his motivation is high as he begins the ATP World Tour Finals in London.

Andy Murray took possession of the No. 1 ranking this week following his title at the Paris Masters.

Djokovic, who recently talked about having a lack of desire, has won just one title since the French Open. But speaking to reporters before the World Tour Finals, the Serb made it clear that he’s still committed to his career.

In addition to reported personal issues, the 12-time Grand Slam champion has also been experiencing some discomfort in his right arm.

"I have plenty of motivation, [and] it starts from within," Djokovic said. "Even after 10-plus years at a professional level, I still feel I have a lot of gas in my tank. I feel like I still have a lot more years ahead of me. I feel great joy when I compete, when I play.

"The power of passion towards the sport is the No. 1 thing that drives me to play, to enjoy to play. This is the game. If you don't enjoy the game—your time on court—everything else becomes two or three, five times more difficult than it is or should be.”

Murray enters the tournament 405 ranking points in front of Djokovic, and the Scot will drop 275 points following the Davis Cup final. Djokovic can move back to No. 1 this season by outperforming Murray at the World Tour Finals.

Ahead of the year-end event, Djokovic praised his friendly rival's rise to the top.

"[He’s] definitely a well-deserved No. 1 at this point," said Djokovic. “…Whether or not he can sustain it is not a question for me … The qualities he possesses as a player, his determination to the sport, there's a good chance that he can still play in this level for some time."

Since the beginning of the clay-court season, Murray has won eight titles and been a runner-up three times.