Maidstone manager George Elokobi said the "magic of the FA Cup is very much alive" after the sixth-tier side stunned Championship high-flyers Ipswich 2-1, while Luton struck at the death to dump Everton out in the fourth round on Saturday.
Ipswich are 98 places and four divisions above Maidstone in the English football pyramid, but manager Kieran McKenna was left to rue making 10 changes.
The visitors' two goals were worthy of winning any cup tie as Lamar Reynolds produced a cool chip over Christian Walton as Maidstone surged upfield from an Ipswich corner just before halftime.
Jeremy Sarmiento looked to have restored order when the Ecuador international drilled low into the bottom corner on 56 minutes.
However, there was another twist in a fairytale story as Reynolds this time played provider for Sam Corne to fire in the winner 24 minutes from time.
"Our boys have run themselves into the ground and that is what we said, 'leave nothing in the changing room'," said former Wolves defender Elokobi.
"This binds us for life, what our boys are achieving right now. What our boys are achieving now has not been done in over 100 years. The magic of the FA Cup is very much alive."
PEDRO HAT-TRICK FOR BRIGHTON
Everton and Luton's priority is survival in the Premier League and the Hatters' 96th-minute winner at least ensured they both avoided a replay.
Vitaliy Mykolenko's own goal gave Luton a halftime lead that was cancelled out when stand-in goalkeeper Tim Krul allowed Jack Harrison's shot through his grasp early in the second period.
A bad-tempered affair appeared to be meandering towards a stalemate until Cauley Woodrow bundled home from a corner right at the death.
Joao Pedro scored a hat-trick, including two penalties, as Brighton beat Sheffield United 5-2 at Bramall Lane.
Facundo Buonanotte's fine strike and Pedro's first spot-kick put the visitors 2-0 up.
But last season's semifinalists were pegged back before halftime as Gustavo Hamer and William Osula struck for the Blades.
Another Pedro penalty restored Brighton's advantage before he completed his hat-trick and Danny Welbeck rounded off the scoring deep into stoppage time.
Newcastle, who last won the FA Cup 69 years ago, eased to a 2-0 victory at Fulham thanks to goals from Sean Longstaff and Dan Burn.
Longstaff's 39th-minute opener was tinged with controversy as he fired home despite Fulham's appeals for handball against Bruno Guimaraes in the build-up.
Burn bagged Newcastle's second goal in the 61st minute with a close-range finish after Sven Botman's effort was saved by Marek Rodak.
It was Fulham's second cup exit in the space of four days after they were beaten in the League Cup semifinals by Liverpool on Wednesday.
Championship leaders Leicester made light work of Birmingham as Jamie Vardy was on target in a 3-0 victory.
Leeds and Plymouth is one of at least four ties set for a replay after they drew 1-1 at Elland Road.
Holders Manchester City booked their place in the last 16 with a 1-0 win over Tottenham on Friday night thanks to Nathan Ake's late winner.
Liverpool are in action on Sunday when they host Norwich at what is sure to be an emotional Anfield for the Reds' first match since manager Jurgen Klopp announced he will leave the club at the end of the season.
Newport County of League Two are also seeking a huge upset when they host Manchester United on Sunday.