Novak Djokovic is ready to fight for his world number one status as Andy Murray heads into next week's Paris Masters looking to overtake the Serb.
Murray, 29, won his third title in as many weeks with victory in Vienna on Sunday and could top the rankings with another good run in Paris.
Four-time champion Djokovic says he is rejuvenated after a slump in form.
"It makes me want to go on court and fight for every point because there is something to win at the end," he said.
The 12-time Grand Slam champion returns to action after losing in the Shanghai semi-finals two weeks ago.
Djokovic, 29, has finished four of the past five years as the world number one and will hold on to the top ranking if he reaches the final in Paris.
However, failure to do so would allow Murray to overtake him if the Scot can win, or if Murray reaches the final and Djokovic falls before the semis.
"I have been in these particular situations before in terms of ranking, so I know what to do, and I just keep things very simple," said Djokovic.
He returns to Paris for the first time since completing the career Grand Slam with a first French Open title in June, but since then his form has dipped.
Djokovic picked up one more title in Toronto but lost early at Wimbledon and the Olympics, and suffered a bruising defeat by Stan Wawrinka in the US Open final.
"Winning the French Open this year has brought a lot of joy to me but on the other hand has taken away a lot from me, as well," said Djokovic.
"I felt a little bit exhausted, I must say, and maybe less motivated. So I had to kind of rediscover that feeling of being on the court and keep pushing myself.
"I guess it took a little bit of time, more time, and I'm in a better state of mind at the moment than I was some months ago."
Murray, in contrast, has won 52 of his past 56 matches, collecting his seventh title of the year in Vienna on Sunday.
"You've got to give him credit for what he's done in the last three or four months - the second part of the year is quite incredible," said Djokovic.
"He's playing maybe the best tennis he's ever played, very consistent, very strong. He definitely deserves to be in the position of being number one at the end of the year.
"But that doesn't just depend on him."
Murray has closed the gap dramatically in terms of points over the past four months and now trails by just 415, with 1,000 on offer to the winner in Paris, but Djokovic has won for the past three years on the indoor courts of Bercy.
"Obviously he could win the event and, if I lose in the first round, then I am a long way from being number one," said Murray.
"I've never won there before, so to just expect that you're going to win the tournament would be silly."
Top seed Djokovic will open his campaign against Gilles Muller or Nicolas Almagro on Tuesday or Wednesday, while second seed Murray will face Fernando Verdasco or Robin Haase.