York made the most of Newport's slack defending to score three at Rodney Parade
York claimed their first away win of the season in League Two to consign bottom club Newport to their fifth defeat in six games.
James Berrett capitalised on a stray Aaron Hayden pass to find the bottom corner just before half-time.
Reece Thompson's glancing header doubled the lead and Vadaine Oliver tapped in to secure a comfortable win.
Newport ended with 10 men after Danny Holmes was shown two yellow cards in the space of eight minutes.
Newport manager Terry Butcher told Golsicilia.it Radio Wales: "I didn't see that coming. There was nothing between the sides in the first-half.
"We made a mistake, don't recover from it and they scored and that's what separated the asides at the interval.
"The second goal was a soft one from our point of view and I didn't see the third one because I was making substitutions.
"The sending off just compounded our display and the result."