The biggest crowd of the season saw Town celebrate Sir Bobby Robson Day in style.
Not even a goal from the returning Daryl Murphy could stop Blues picking up a deserved win, with Emyr Huws rounding off the scoring with a superb volley in added on time.
Freddie Sears had given Town the lead at the break, before Murphy struck on the hour, the former Blue keeping his celebrations muted. David McGoldrick put Mick McCarthy’s side back in front soon after and Huws sealed the win from Brett Pitman’s cross.
Sears was a constant threat to Newcastle and could have had more than the one goal, while McGoldrick also went close to adding a third late on.
Town stayed with the same side that beat Burton on Friday, Dean Gerken still absent with a shoulder problem.
Murphy was given a warm reception from the Town fans as he made his first return since leaving the Club for Newcastle in August.
Town started brightly and Sears found space down the left flank but Karl Darlow was equal to the task, taking the cross as it headed for McGoldrick.
Sears then won a free-kick as he burst towards the Magpies’ backline and from Tom Lawrence’s delivery, the ball beat everyone and landed in the net but the referee’s whistle brought the celebrations of the Blue Army to an immediate halt.
Luke Chambers did superbly to block the danger from Paul Dummett, while at the other end Darlow had to be quick off his line to smother the danger from McGoldrick after Sears had again threatened coming in from the left.
Bart Bialkowski punched clear from Jonjo Shelvey’s free-kick, Murphy then seeing a header deflected over, Dummett firing wide from the resultant corner.
Lawrence fizzed an excellent cross from the right that Jamaal Lascelles cleared at full stretch, McGoldrick hooking a left foot shot from the edge of the box over as Town edged the first half hour.
Bialkowski comfortably dealt with Shelvey’s 25 yarder, the midfielder then testing the Town ‘keeper with a vicious strike before Matt Ritchie sent a diving header over the bar from Dummett’s cross.
Moments later, Town were ahead. Myles Kenlock won possession on the halfway line, Lawrence burst forward and Sears did the rest with a clinical finish from 12 yards to make it four goals in his last three games.
Sears turned provider a minute later, his cross found McGoldrick, the Republic of Ireland international’s shot deflected over, then Sears was denied again as Town pressed for a two goal cushion at the break.
Ritchie looked to get in at the far post from Dummett’s cross but Kenlock cleared the danger as the second-half got underway, Lawrence then sending a free-kick over the bar.
Yoan Gouffran replaced Isaac Hayden on the hour and seconds later Newcastle were level, Christian Atsu sent in a terrific cross and Murphy sidefooted the ball home.
Town were back in front eight minutes later, Sears again found space inside the Newcastle box and his shot was passed into the empty net by McGoldrick.
Chambers cleared from Ritchie’s cross, Newcastle’s Scotland international then conjuring up another cross that McGoldrick volleyed clear.
Josh Emmanuel replaced Kenlock for the closing stages, Grant Ward curling a right footer over the bar as Town looked for a killer third goal.
McGoldrick almost provided it, Darlow’s fingertips doing enough to divert his chip over the bar, while at the other end Aleksandar Mitrovic was denied by first Chambers and then Bialkowski.
It was left to Huws to have the final say, the Wales international thumping in a volley at the far post from Brett Pitman’s cross to seal an impressive win for Town and dent Newcastle’s promotion bid.
Town: Bialkowski, Spence, Chambers, Berra, Kenlock (Emmanuel 76), Skuse, Huws, Ward, Lawrence (Pitman 89), Sears, McGoldrick (Smith 86). Subs not used: Crowe, Bru, Diagouraga, Samuel. Booked: McGoldrick, Lawrence.
Newcastle: Darlow, Dummett, Yedlin (Gamez 78), Lascelles, Hanley, Shelvey, Ritchie (Mitrovic 81), Diame, Hayden (Gouffran 60), Atsu, Murphy. Subs not used: Elliott, Colback, Perez, Mbemba. Booked: Hayden.