For roughly a decade, tennis has been dominated by three players: Roger Federer, Rafael Nadal and Novak Djokovic. Since 2008, the trio has won a combined 36 Grand Slam singles titles, thus prompting constant debates in how their legacies compare.

This week promises to have more competition from the tennis legends, as the year-end No. 1 ranking is up for grabs at the Paris Masters.

Federer on Sunday captured his ninth Swiss Indoors title with a 7-6 (7-5) 6-4 victory over Marius Copil. The 37-year-old is now just one win away from his 100th ATP title.

But Federer winning in his hometown of Basel is not a major feat when compared to the challenge that awaits him in Paris. The Swiss legend has an ominous draw at the Paris Masters that may mean he has to defeat Nadal, Djokovic and Kevin Anderson to reach the century mark.

Nadal, arguably the greatest French Open player in history, will be making his return after a knee injury. But the Spaniard has never won the Paris Master and has only reached the final of the hardcourt tournament once. After a first-round bye, Nadal faces either fellow countryman Fernando Verdasco or Frenchman Jeremy Chardy in the second round.

Nadal, 32, has not played since reaching the U.S. Open semifinals in early September. He will be looking to maintain his No. 1 ranking with Djokovic breathing down his neck.

The Serb is the favorite to win the tournament. According to Sky Bet, Djokovic has 6/5 odds to win the Paris Masters and is followed by Federer at 5/1. Nadal has the third-best odds at 6/1.

Djokovic, who has won the Paris Masters a record four times, is coming off Wimbledon and U.S. Open wins. The 31-year-old most recently won the Shanghai Masters and has not conceded a set in his last 10 matches.

Nadal has a slim lead over Djokovic in the ATP rankings. Nadal has 7,660 points, while Djokovic has 7,445. Federer is third with 6,260 points.