Del Potro fell on his left hand at the start of the third set of this tightly-contested quarter-final.
The Argentine was seen to by a physio and was evidently in pain as he sat on his chair.
He was able to continue after proving he could hold his racket in his left hand.
But the 2016 Olympic finalist refused to play any double-handed backhands in order to avoid the pain.
Not that his reduced arsenal affected his game, with Del Potro readjusting his tactics to play more off the forehand and utilise his backhand slice.
Troicki was broken in the same game Del Potro went down and the match went with severe until the 29-year-old rounded it off 4-6 6-1 6-4.
Next up for Del Potro is a semi-final clash against either Roger Federer or Richard Gasquet.
But the Argentine will no doubt have someone look at his left thumb and wrist to assess the extent of the damage done today.