Local boy Harry Clifton ensured that League Two Grimsby Town earned themselves a replay at Luton and with it the prospect of fishing out a plumb fifth round draw.
Moments after falling behind having squandered a first-half lead, Clifton drove forward to spear in a deserved 67th-minute equaliser at Kenilworth Road.
The midfielder, who came through the ranks at his boyhood club, even had the chance to cause an FA Cup shock late on, but scuffed his shot and saw it cleared by Luton substitute Fred Onyedinma.
Gavan Holohan gave the Mariners a shock lead with a header just before the half-time whistle
Elijah Adebayo got the hosts back level on 49 minutes with a well converted penalty kick
Jordan Clark gave Luton the lead for the first time in the game on 66 minutes from inside the box
Backed by nearly 1,500 Mariners fans and at least 100 inflatable haddocks, the visitors belied their status to harry mid-table Championship side Luton at every turn.
Elijah Adebayo skied an early shot for the hosts, but that was the sum total of their efforts in an even first period.
Indeed, it was Grimsby who took the lead just before the interval.
Gavin Holohan sized up a bouncing ball and let fly from 25 yards with a volley that dipped viciously at the last second, causing Horvath to tip it over at full stretch.
Rob Edwards’ side failed to beat the side starting the day 57 places below them in the Football League
A deep corner then reached the midfielder whose header possessed direction but seemed to lack the power needed to beat Horvath.
Somehow, though, it squeezed past the Luton keeper and into the far corner to give the League Two side the lead.
It took Luton just three minutes of the second half to equalise. Bryn Morris tripped Gabe Osho to give Adebayo the chance to beat Max Crocombe from the penalty spot.
When Jordan then sent in a thigh-high shot which struck Crocombe’s hand but still spun over the line, it seemed that Luton would seal their passage.
Instead, Clifton equalised less than 60 seconds later to leave Grimsby hoping for a first fifth round tie since 1996.