The World No.1 and World No.2 had a rare practice in Bercy.
The Greek looks forward to his third meeting with Roger Federer in 2019.
The eight player field for the season-ending 21-and-under event is set.
World No. 1 says reaching Federer's record isn't only goal.
The groups are set and play will begin on Sunday at the Shiseido WTA Finals
World No. 2 on what's next after his October 19th wedding.
The Canadian injured his left ankle while practicing in Vienna.