The conditions at the season finale in London are expected to be slightly heavier, but being indoors, with the elements not playing a part, the setting is ideal for Federer's precisely directed weaponry.
Amnesty International had urged Nadal and Djokovic not to play.
"Novak is obviously on a roll, you can feel it", he said after the Paris loss.
The 31-year-old Djokovic underwent surgery on his right elbow in January after the Australian Open, which was his first tournament in six months. "I'll play with confidence", he said. "Reflecting on what I've been through in the past year, it's quite a phenomenal achievement", said Djokovic, who was No. 2 last week and hadn't been No. 1 since November 2016. This will be whittled down next month to a shortlist of about five and a final decision on the host of... "It turned out to be a ideal five months".
The 31-year-old looked tired in his defeat to the Russian big-hitter Karen Khachanov in the Paris Masters final, but there is no denying that he is back to his sliding, defending, counter-punching best.
PM's Brexit plans under pressure after Jo Johnson resignation and DUP warning
The Government has ruled out a second referendum. "I think a second referendum would be divisive, but it wouldn't be decisive". He added: 'This is one of the most momentous questions we will ever face in our political careers.
After then enjoying the hospitality of Her Majesty's government in a setting as far removed from ordinariness as it is possible to get, they return to their day jobs on Sunday, Federer lighting up the evening programme against Kei Nishikori. The match marks a rematch of the US Open final where the All-American duo beat them in straight sets. "The 6'8" Anderson had battled to victory after being two sets and match points down (in third set) against Federer in the Wimbledon quarter-finals. Ten more titles is a big task at age 37 with a limited tournament schedule, and there are plenty of other obstacles beyond his direct control. "It's been a good place for us to play to showcase our talents". "I just feel the concept of this event should be the one that travels".
"I look at this next generation, Nishikori, Raonic and Dimitrov, as the one which came after Pete Sampras and Andre Agassi".
But Jimmy Connors's Open-era men's record of 109 titles has hardly been Federer's white whale, some career-long obsession that has kept him up nights or inspired him to do a round of extra sprints in Dubai, United Arab Emirates, with the fitness coach Pierre Paganini. Check back to see if the rising star can knock out some of the sport's greatest players.
With more players still to be announced over the coming weeks, the tournament is shaping up to be one of the most well rounded in recent times with strong fields for both the Women's and Men's weeks already confirmed.