Three-times champion and world number one Novak Djokovic has been drawn in a group with U.S. Open champion Marin Cilic in next week's season-ending ATP World Tour Finals in London.
Defending champion Djokovic, who retained his Paris Masters title on Sunday after beating Milos Raonic, will also face Australian Open champion Stanislas Wawrinka and hard-hitting Czech Tomas Berdych in Group A of the elite event staged at London's o2 Arena.
Cilic is making his debut at the eight-man event.
Second seed Roger Federer, who has won the year-ending tournament six times and who still has hopes of replacing Djokovic on top of the rankings before the end of the year, faces a clash in Group B with home favourite Andy Murray.
Debutants Raonic and Japan's Kei Nishikori, the first Asian-born man to qualify for the showpiece event, complete the group.
Former Wimbledon champion Murray, who won three titles in the past six weeks to secure a place at the tournament after slipping down the rankings, missed last year's tournament because of back surgery.
World number three Rafael Nadal of Spain is missing because of surgery for appendicitis.
The lucrative tournament gets underway on Nov. 9.
