Andy Murray will begin his ATP World Tour Finals campaign as World Number One for the first time in his career when he faces Marin Cilic today.
The week-long tournament will see eight of the best in tennis singles and doubles battle it out in the season-ending championships at The O2.
For the round-robin phase, ‘Group John McEnroe’ will consist of World Number One Murray, No. 3 Stan Wawrinka, No. 5 Kei Nishikori and No. 7 Marin Cilic.
Murray will go up against the stronger and more in-form players than Novak Djokovic faces.
Wawrinka is coming off the back of a US Open victory and has proven himself in the round-robin stage against Murray, beating the Scot last year to advance into the semi-finals.
Nishikori has shown that he has potential against Murray, after knocking him out in the quarterfinals at the US Open in September.
Cilic is in tantalising form, knocking Djokovic out of the Paris Masters a week ago, opening the door for Murray to take the top spot from the Serb.
‘Group Ivan Lendl’ will consist of World Number 2 Djokovic, No. 4 Milos Raonic, No. 6 Gael Monfils and No.9 Dominic Thiem.
Djokovic should find it easier than Murray to make it through to the semi-finals.
Raonic withdrew from the Paris Masters – which gave Murray his number one status – with a torn quad so if he does defy odds and make it to the tournament, he will be far from his best.
Monfils has never won a match against the Serb, despite 13 attempts to do so.
Thiem found himself in the competition after Rafael Nadal ended his season early with a wrist injury last month.
The ATP World Tour Finals ends on Sunday 20th November.