Juan Martin Del Potro clambered off the court floor to knock out Serbia’s Viktor Troicki 4-6, 6-1, 6-4 and bravely seal a spot in the semi-finals of the Shanghai Masters on Friday.

The Argentine 16th seed faces Swiss great Roger Federer or unseeded Frenchman Richard Gasquet on Saturday for a place in the final.

Del Potro, who has suffered years of wrist injuries that have threatened his career, took a nasty tumble at 2-2 in the deciding set.

His foot appeared to get stuck on the floor and he crumpled down, landing with his weight on his outstretched left hand – his non-playing hand – and bending it painfully backwards.

He needed several minutes of medical attention and sat on a chair on the back of the court, wincing in obvious distress.

Incredibly, he broke the serve of the unseeded Troicki on his immediate return to action.