Andy Murray will meet Novak Djokovic in the group stages of the Barclays ATP World Tour Finals after the draw was made in London.
As number three seed, the US Open champion was guaranteed to face either Djokovic or Roger Federer in the round robin stages of the season-ending tournament, which begins at the O2 on Monday.
As well as Djokovic, Murray will also face fifth seed Tomas Berdych and seventh seed Jo-Wilfried Tsonga in what looks significantly the tougher of the two groups.
The top eight players over the season qualify for the tournament, although Rafael Nadal is absent through injury, meaning his Spanish countryman David Ferrer takes over as fourth seed.
Ferrer is in Group B with defending champion Federer, who will lose his world number one ranking to Djokovic on Monday, sixth seed Juan Martin Del Potro and eighth seed Janko Tipsarevic.
The draw guarantees at least one meeting between Murray and Djokovic, continuing a rivalry that has quickly developed into the sport's most compelling of the moment. As well as the US Open final, where Murray won his first grand slam title in a dramatic five-set match, the pair also met in the final of the Shanghai Masters last month.
On that occasion, Murray held five match points but it was Djokovic who eventually came out on top.
Murray will be looking to end his season on a high with a first title at the World Tour Finals, a tournament Federer has won a record six times. In four previous appearances, Murray has twice reached the semi-finals, most recently in 2010, when he lost an epic three-setter to Nadal.
The tournament is being held at the O2 for the fourth time after moving from Shanghai on a five-year contract in 2009, and organisers are expecting record attendances. There is a prize pot of more than £1million available for an undefeated champion and 1,500 ranking points.