Watch five of the best shots from Novak Djokovic's 6-2 6-2 victory over Tomas Berdych, which saw him reach the last four at the ATP World Tour Finals in London.
Djokovic's 30th straight indoor victory means he tops Group A and will end the year as world number one.
Kei Nishikori awaits the in-form Serb in Saturday's semi-final.
Watch live coverage of Djokovic v Nishikori on Saturday on BBC Two, the BBC Sport website and on Connected TV from 14:00 GMT, with commentary of both semi-finals on Sports Extra.
Available to UK users only