LONDON, Nov 11 (Reuters) - For a set not even the granite defence of Novak Djokovic could withstand the irresistible brute force of Juan Martin del Potro on Sunday but the Serb then rode out the storm to win the opening semi-final at the ATP World Tour Finals.
The world number one soaked up some wrist-bending blows from the inspired Argentine before turning the match in his favour to romp home to a 4-6 6-3 6-2 victory at the O2 Arena.
Djokovic, the only player in the eight-man event to win all three round-robin matches, will face either defending champion Roger Federer or Britain's Andy Murray in Monday's final.
He struggled to live with Del Potro's weight of shot in the openign set and was in trouble when he went a break down in the second but once again he showed the qualities that have made him such a hard player to beat.
Djokovic broke Del Potro's serve twice im the second and third sets and surged to victory in two hours 11 minutes. (Editing by John Mehaffey)