The cross Severn rivals had not faced each other in a competitive fixture since Rovers claimed the spoils 25 years ago.
But a first-half penalty from former Rovers winger Sandell ensured the hosts continued their impressive return to the Football League.
County dominated the opening exchanges at Rodney Parade, with Christian Jolley and Adam Chapman threatening.
The deadlock continued despite their dominance as Chris Zebroski fired narrowly wide.
The visitors clung on with heroic defending denying both Jolley and Zebroski.
But Newport eventually got the breakthrough when Jolley took the ball past John-Joe O'Toole and was hauled down in the area.
Lee Collins had no choice but to award a penalty and Sandell promptly sent Steve Mildenhall the wrong way.
Rovers returned with far more purpose in the second half but Newport held firm.
And Conor Washington should have doubled their lead after breaking through but Mildenhall was more than a match.