Peter Leven's 71st-minute penalty and Puncheon's last-minute rocket ensured a fifth straight defeat for the Pirates, for whom substitute Darryl Duffy netted a stoppage-time consolation goal.
"Punch has been working extremely hard on the training ground to round off parts of his game which are maybe not as strong," said Robinson. "He knows his right foot could be better - he works on that every day.
"He stays behind and it's pleasing for him to get the goal because it shows all the practice and effort he's putting in is starting to pay off."
On the game itself, Robinson added: "It was a solid, strong second half performance with us playing at a tempo that Bristol Rovers couldn't cope with. We had 76 per cent of the possession in the first half too, which is frightening. We moved the ball quicker in the second half and we got our rewards."