London – Novak Djokovic cut giant Argentine Juan Martin del Potro down to size as the world number one battled into the final of the ATP Tour Finals with a 4-6, 6-3, 6-2 victory on Sunday.

Djokovic will play defending champion Roger Federer or third seed Andy Murray in Monday's final after coming from a set and a break down to topple the 6ft 6in former US Open champion in a gruelling semifinal clash lasting two hours and 11 minutes at London's O2 Arena.