Andy Murray missed out on a place in the last four at the ATP World Tour Finals as Stan Wawrinka won their final group match in straight sets.
The Swiss fourth seed came through 7-6 (7-4) 6-4 in London and will play Roger Federer in Saturday's semi-finals.
World number one Novak Djokovic will take on fifth seed Rafael Nadal in the other half of the draw.
Murray heads to Belgium next week for Great Britain's first Davis Cup final since 1978.
No let-up from Nadal
Nadal warmed up for his semi-final against Djokovic with a 6-7 (2-7) 6-3 6-4 win over fellow Spaniard David Ferrer in his final round-robin match.