Goals from Ryan Fraser, Sean Longstaff and Callum Wilson ensured that the Toon Army enjoyed their first away match since a 1-0 win at Southampton in March 2020, and the supporters were the real stars of the show in South Yorkshire.
But there were also plenty of impressive performances on the pitch as Steve Bruce's side were much-improved from Sunday's defeat at York City.
And there were senior Newcastle debuts for Morpeth-born 20-year-old Jack Young, who has been with the club since the age of seven, and England under-18 international Matt Bondswell, who both came off the bench in the second half.
Fraser - fresh from featuring for Scotland at Euro 2020 - opened the scoring in the 12th minute with an excellent low drive from outside the box before Longstaff made it two in the 24th minute, prodding home from close range from a Jamal Lewis cutback after fantastic work on the left from Allan Saint-Maximin.
Tommy Rowe pulled a goal back on the half-hour, slotting home the rebound after Dan Langley had kept out a deflected long-range strike.
But Wilson - who had been typically dangerous throughout the first half - extended United's lead in the 56th minute, slotting past Louis Jones after latching onto Fraser's inch-perfect pass.
One of several trialists for the home side was unlucky to see a curling effort hit the bar in the 69th minute but Newcastle should have added another when Fraser missed from close range, then Jacob Murphy flashed an effort just wide after a superb solo run.
Doncaster set up an exciting finish when Omar Bogle headed home in the 76th minute, but United sent their fans home happy with a deserved win.
Newcastle United: Dan Langley, Jacob Murphy (Tom Allan 82), Isaac Hayden (Federico Fernández 57), Jamaal Lascelles (c), Kell Watts 82), Paul Dummett (Ciaran Clark 70), Jamal Lewis (Matt Bondswell 85), Jeff Hendrick, Sean Longstaff, Ryan Fraser (Jack Young 76), Allan Saint-Maximin (Dwight Gayle 67), Callum Wilson (Matty Longstaff 67)
Subs not used: Max Thompson, Oisín McEntee