Novak Djokovic insists he has no problem finding inspiration to continue in tennis despite his recent dip in form.
Djokovic was deposed as world number one by Andy Murray at the Paris Masters, the Serb's quarter-final loss to Marin Cilic proving costly when Murray progressed to the final - which he went on to win against John Isner - to seal top spot courtesy of Milos Raonic's last-four withdrawal.
The 12-time grand slam champion will attempt to win his first tournament since the Rogers Cup in July when he defends his ATP World Tour Finals title in London next week.
Asked about his passion for the sport, Djokovic told a media conference: "You do have days when you're feeling less determined to really play than some days that you feel more.
"As long as the days where you feel more positive are making the majority of those days then things are going well.
"That's the case with me. Even after playing 10-plus years in a professional tennis level, I still feel I have a lot of gas in my tank and I feel I still have a lot more years ahead of me. I feel great joy when I compete, when I play.
"Practice days make up probably 80 per cent of our season, that's when you really need to get that inspiration and get that drive going on a daily basis so you can maintain that level of determination and be able to compete at the highest level at tournaments like this.
"Fortunately for me at this stage I don't have the problem of really finding motivation or sources of inspiration, I have plenty of them.
"My mindset is very positive towards the sport and towards the life that I have. In addition to that I have the great support of my family, as long as it's like that I'll be around."