Eddie Howe fielded two almost entirely different XIs, with Kell Watts the only player to complete the full 90 minutes, while new signings Sven Botman and Nick Pope - along with the likes of Bruno Guimarães, Fabian Schär and Chris Wood - watched on from the sidelines having been granted extended breaks after representing their respective national teams earlier in the summer.
They are all likely to be involved in United's training camp in Austria next week, but Howe will take plenty of positives from this first friendly against Mike Williamson's men, who were promoted to the National League last term and included former Newcastle youngsters Tom Allan, Greg Olley, Louis Storey, Owen Bailey and Dan Ward.
Elliot Anderson started for United after his eye-catching loan spell with Bristol Rovers last season and he created the first opening of the match with a low cross from the left, with Joe Willock firing over the bar.
And the teenager then came close to scoring himself when Jonjo Shelvey's inch-perfect pass found Ryan Fraser, who cut the ball back to Anderson only for his goalbound shot to be deflected behind. The resulting corner was taken by Fraser and headed narrowly off target by Shelvey.
The visitors could and perhaps should have taken the lead when Paul Blackett shot wide from ten yards before the same player saw a dangerous low cross well held by Martin Dúbravka soon afterwards.
But it was the Magpies who went in front in the 31st minute when Anderson's cross from the left fell to Ritchie, who took a touch and finished well beyond Gateshead goalkeeper Dan Langley, who is on loan with the Heed from Newcastle.
And United ended the first period strongly, with Shelvey shooting wide after a sustained spell of possession before Ritchie was denied by a good Langley save, with the goalkeeper then holding another powerful effort from Ritchie on the stoke of half time.
Less than two minutes into the second half, the much-changed Magpies doubled their advantage when Sean Longstaff was brought down in the box and Joelinton stepped up to emphatically net from the penalty spot.
Jacob Murphy had the ball in the net seconds later from a wonderful Matt Targett cross, but the flag went up for offside, then substitute goalkeeper James Montgomery made two excellent saves from Allan Saint-Maximin and then Longstaff, who was joined in midfield by younger brother Matty for the second 45 minutes.
Blackett pulled one back for the Heed as he rounded Karl Darlow and slotted home following Olley's pass, but Newcastle had the chance to stretch their lead when Joelinton was fouled after a strong run into the box, only for Sean Longstaff to send his spot-kick over the bar.
Montgomery made another good stop to thwart Almirón after a through-ball from Allan Saint-Maximin, but he could do nothing to prevent the Paraguayan from making it 3-1 ten minutes from time after he outpaced the defence to race onto Krafth's pass and finished neatly.
And, after Targett had headed just over the bar, Almirón scored his second and United's fourth with a near carbon copy before Sean Longstaff rounded off the scoring in the last minute, slotting home after great work from Saint-Maximin and Joelinton.
Newcastle United (first half): Martin Dúbravka, Kieran Trippier, Jamaal Lascelles, Kell Watts, Paul Dummett, Jonjo Shelvey, Elliot Anderson, Joe Willock, Matt Ritchie, Ryan Fraser, Callum Wilson
Newcastle United (second half): Karl Darlow, Emil Krafth, Kell Watts, Dan Burn, Matt Targett, Matty Longstaff, Joelinton, Sean Longstaff, Miguel Almirón, Allan Saint-Maximin, Jacob Murphy
Subs not used: Remi Savage, Jay Turner-Cooke