#2 Rafael Nadal
Since being forced to retire against Juan Martin Del Potro in the semi-finals of the US Open, Nadal pulled out of the Laver Cup and also didn't take part in the Asian leg of the ATP Tour. The popular Spaniard earned many plaudits for his noble efforts to assist in flood rehabilitation work in his native Mallorca.
The Spaniard will look to fend off the challenge of Novak Djokovic and retain his Number 1 ranking and also look to win his first Paris Masters title. Likely to face off against fellow Spaniard Fernando Verdasco in the opening round, a potential quarter-final against Dominic Thiem or Borna Coric awaits and if he wins his quarter-final, a match against Alexander Zverev beckons in the semi-finals.
With the Paris Masters being only one of two Masters titles (the other being Miami Masters) not in Nadal's trophy cabinet, he will look to seize his opportunity and also retain the Number 1 ranking.
#1 Novak Djokovic
In ridiculous good form since his win at Wimbledon, Novak Djokovic is the clear favourite to win the Paris Masters and extend his streak there to 5 titles. From losing to Marco Cecchinato at the French Open, Djokovic has made giant strides in discovering his dominating form which he showed in 2015.
His serve, which was an issue earlier this year, looks to have been rectified and there are really no chinks in his armour now. If the Serb manages to win his 5th Paris Masters, he will not only reclaim the Number 1 ranking for the first time since 2016, but also tie Rafael Nadal's all-time ATP Masters tally of 33 titles.
Since winning at Cincinnati and Shanghai, Djokovic will look to add another Masters title in addition to his 2 Grand Slam titles. A third round match against Stockholm Open winner Stefanos Tsitsipas awaits before a quarter-final showdown against either Marin Cilic or Grigor Dimitrov.
If he manages to ace that challenge, Novak would be up against Federer in the semi-finals and a potential final against current World Number 1 Rafael Nadal beckons.
What is the foot injury that has troubled Rafael Nadal over the years? Check here