Phil Foden shone for Manchester City as they booked their place in the FA Cup quater-finals, but they were pushed all the way by their League Two rivals.
With the scores level at the break, Leroy Sane grabbed the opener, before Phil Foden grabbed his first.
Padraig Amond pulled a goal back for the Welsh outfit, before Foden grabbed a second. Riyad Mahrez added a late fourth.
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FA CUP MATCH FACTS AND MATCH ZONE
Newport County: Day, Poole, O'Brien, Demetriou, Willmott, Bennett, Bakinson, Labadie, Butler, Matt, Amond.