Novak Djokovic will try to win a record fourth consecutive season-ending title when he takes on Roger Federer at the ATP World Tour Finals on Sunday.
Djokovic, 28, hopes to surpass Ivan Lendl, who won his third straight Tour Finals in 1987.
Federer will be buoyed for his 10th final in this event after beating Djokovic in the group stage on Tuesday.
The 34-year-old had been set to face the Serb in last year's final but had to pull out with a back injury.
I don't feel unbeatable - Djokovic
Djokovic has won 81 matches, 10 titles and three Grand Slams as he secured the end-of-season number one ranking for the fourth time in five years.