NOVAK Djokovic, the world's second best tennis player. It seems strange to regard the 29-year-old in this manner, stranger still that the relentless Serbian now seems to concede that there is more to life than winning tennis matches. Perhaps it is his work with Spanish spiritual guru Pepe Imaz that his granted the 29-year-old this enlightenment but it is worth remembering that winning tennis matches is all Djokovic ever does at the o2. You have to go back to 2011 and a round robin meeting with his countryman Janko Tipsarevic to find the last time Djokovic lost at this swish London venue and if he achieves the same at the ATP Tour finals this week then he will have done enough to reclaim his customary habitat at the summit of the world rankings, limiting Andy Murray's hold on top spot to just a fortnight. Not, heaven forbid, that he is hell-bent on achieving precisely that.

"Grand Slams and I guess the No 1 in the world is probably the pinnacle of our sport, it has been like that for decades," said Djokovic. "But I guess everyone is different. On one hand I surely value Grand Slams and No 1 in the world as one of the highest goals of myself as an athlete. But I also don't look at results as the only way of measuring the success of my career. How healthy I am when I finish the season, physically, mentally? Did I injure myself or am I not able to play with my son [Stefan] and do the everyday things in life which count more than winning any trophy in life?

"I have only words of praise for what he [Murray] has achieved in the last year or so," the Serb added. "He has had an incredible run and is definitely a well deserving No 1 player. Whether or not he can sustain that is not a question for me."

Djokovic took umbrage at the suggestion that he had "not emotionally been himself" in the last few months, and insisted he still finds great joy and motivation at practice most days. He has been back on the practice court with Boris Becker in London this week, as he plots the perfect way to spoil the Scot's party. He has located one of the softer groups in the history of this competition, pitched against an injured Milos Raonic and two first time players, Gael Monfils and Dominic Thiem, with the Austrian first up tomorrow.

"You do have days when you are feeling maybe less determined to play and some days you feel more," said Djokovic. "But even after playing ten plus years, I feel like I still have a lot of gas in my tank and still a lot more years ahead of me. I don't have a problem finding motivation, it starts from within. My mindset is very positive towards the sport and the life and lifestyle I have. Great support from my family and my wife is important. As long as it is like that then I will be around. I have had an amazing last four years in the o2 arena and I am hoping I can carry on with the great results I have had."