Indoor finale just fine by Federer amid clay talkSports | Nov 14, 2017
The season-ending event has never been held on clay since its inception in 1970, and it's a tournament which world No 1 Nadal has yet to conquer. It has mostly been played on an indoor hardcourt, with other stints on carpet, grass and outdoor hardcourts.
Federer has always thrived on the indoor hardcourt used at London's O2 Arena, as he showed again by kicking off his bid for a seventh title with a 6-4, 7-6 (7/4) win over American Jack Sock.
Asked about his rival Nadal's desire for a clay-court finale to the season, Federer insisted the current surface was a good choice - given the preponderance of other events on clay. "Fair? I'm not sure if it's the right word. I think it's right and fair that it's indoors, as well," he said. "...You can do indoor clay, I guess, but that's a bit silly. But I get [Nadal's] point."