Spanish tennis star Rafael Nadal got the better of South Korean Hyeon Chung 7-5, 6-4 to advance into the Paris Masters third round.
"I can see Roger getting to 20, 21 by the end of next year possibly and Rafa is going to win a few more French's so it will be very, very close".
The 31-year-old said he would try his best to be present at the eight-man event that takes places from November 12-19 at the O2 in London but his focus was on the long term.
"I can not talk about London now", he added.
"I have to pull out".
Nadal, who beat Pablo Cuevas in three sets Thursday, is 18-1 since the start of the US Open.
"For me it's not about London. For..."
"I am on a good dynamic, playing well the whole season", Nadal, who has only won two of his 75 ATP titles indoors, added.
Paris Masters tournament director Guy Forget acknowledged Nadal's withdrawal was a serious blow to an event often hit by late retirements at the end of the season, and said that the Spaniard's participation in the Tour finals was unlikely.
His compatriot Jack Sock can also snatch a ticket to London with tournament victory in Paris, and he takes on Fernando Verdasco in the last quarter-final later on Friday.
Analyzing the topic on Sky Sports, Annabel Croft said she thinks Novak Djokovic, Andy Murray and others' decision to shut down their season was partly borrowed from having watched Nadal and Roger Federer benefiting from doing so similarly, in 2016. "In the third set, I didn't have much left in my legs".
The 35-year-old had not managed a win over a top-10 player since 2014 before this week, but has now claimed two in as many days after knocking out seventh seed David Goffin in the last 16.