The Magpies made it two pre-season victories out of two with a 2-1 win against Barnsley on Saturday.
Andy Carroll gave the Magpies the lead at United's Benton training ground - his second goal in two games - before Marcel Ritzmaier levelled for the Sky Bet Championship side.
But substitute Jacob Murphy capped a lively showing by netting the winner from the penalty spot after he had been brought down following a strong run on the right.
Jeff Hendrick made his Magpies bow after signing a four-year deal on Monday, and Serena Taylor brought nufc.co.uk this gallery.