Britain's Andy Murray will play U.S. Open champion Juan Martin del Potro in the opening Group A round-robin match of the ATP World Tour finals on Sunday.
World number one Roger Federer, who lost to Argentine Del Potro in the U.S. final at Flushing Meadows in September, meets Spain's Fernando Verdasco in the day's second game at London's O2 Arena.
Spain's Rafael Nadal begins his campaign in Group B on Monday afternoon against Robin Soderling, the Swede who ended his four-year reign at the French Open in May.
Soderling, beaten in the Roland Garros final by Federer, has replaced American Andy Roddick who withdrew from the event on Tuesday with a knee injury.
Serbian Novak Djokovic, the world number three who won the Tour title in Shanghai last year, plays Russian Nikolay Davydenko in Monday's late session in the world's biggest indoor tennis event.