Abu Ogogo struck a stunning injury-time winner at the end of the second half to fire Shrewsbury Town past Grimsby Town and into the Emirates FA Cup Third Round Proper.
The midfielder followed up on a save from Sullay Kaikai's shot to rifle the ball into the far right corner from the edge of the box after the Second Round replay looked set for extra time.
Shrewsbury will face Championship side Cardiff City away in the Third Round Proper.
Manager Micky Mellon made three changes to the side which drew 1-1 at Peterborough United in Sky Bet League 1 on Saturday.
Zak Whitbread, Liam Lawrence and Tyrone Barnett all started in place of Nathaniel Knight-Percival, Ian Black and Jordan Clark.
Shrewsbury lined-up in a 4-4-2 midfield diamond formation , with Scott Vernon at the tip of the diamond, Lawrence and Sullay Kaikai either side and Abu Ogogo in the holding role.
Grimsby got the game underway with Shrewsbury attacking the Pro-Vision CCTV Stand in the first half.
The Shrews made the slightly stronger start with Kaikai's early burst down the inside left halted, although Lawrence had to put in a block at the other end as Jon-Paul Pittman shot just inside the box.
In the 10th minute, Kaikai saw a free-kick from around 25 yards out fly well over the crossbar.
And five minutes later, the ball fell kindly for Scott Vernon to shoot from 20 yards out, but his effort flew straight at the goalkeeper at mid-height.
The Mariners' Pittman was forced off with what looked to be a shoulder injury in the 23rd minute, Omar Bogle was his replacement.
But Paul Hurst's side should have taken the lead in the 25th minute when Conor Townsend crossed at mid-height from the left and Craig Clay controlled the ball around 15 yards out before turning and firing over the bar with his left foot.
Shrewsbury were also forced into a first-half change and Jermaine Grandison looked to be injured, Dominic Smith was his replacement at right back.
Two minutes before the break, Grimsby substitute Bogle turned on the edge of the box and fired a half-volley well over.
The striker then spurned an opening with a scuffed effort wide inside the boxx.
But Pittman's effort aside, neither team were able to create clear goalscoring opportunities in the first period - and it remained goalless at the break.
HALF-TIME: Shrewsbury Town 0-0 Grimsby Town
There were no changes for either side at the break as Shrewsbury got the second half underway, attacking the Salop Leisure Stand.
And the first chance of the half fell for substitute Smith as he collected the ball just outside the penalty area on the right from Brown's cross and shot straight at the goalkeeper at the near post.
There was also a second injury problem for Micky's side in the second half as defender Whitbread was forced off with Knight-Percival his replacement.
59 - Conor Townsend curled over a free-kick.
Bogle then found space in the Shrewsbury penalty on the right just past the hour mark, moved onto his right foot past Knight-Percival before blasting high into the side netting.
At the other end, with 64 minutes on the clock, Kaikai picked Junior Brown out in space on the left, just outside the box, and the full back stepped inside before shooting just wide of the right post with his weaker foot.
But the biggest moment of the second half came when Shrewsbury goalkeeper Mark Halstead made a world-class save.
Grimsby's Craig Clay crossed from the left and Nathan Arnold looked certain to score as he sent a bullet header to the top right corner at the far post from inside the six-yard box.
But Halstead's reflexes were superb and he turned the ball away one-handed to prevent a certain goal.
Micky then opted for his final change with Black coming on for Barnett, but the chances were going Grimsby's way.
Halstead had to make another smart stop with five minutes left when he latched onto Brown's misdirected header in the area on the right and struck fiercely first time to the near post with Halstead having to turn the ball behind.
There was then another let-off for the Shrews from the resulting corner on the right as Gowling headed just wide of the left post unmarked from Townsend's cross.
But just as the tie looked set for extra time, Ogogo popped up with the winner inside two minutes of the additional three at the end.
First, Kaikai saw a low shot from the left well saved.
But the ball came back for Ogogo on the edge of the box and he rifled the ball into the far right corner on the half-volley.
FULL-TIME: Shrewsbury Town 1-0 Grimsby
SHREWSBURY TOWN LINE-UP: Mark Halstead (GK); Zak Whitbread (Nathaniel Knight-Percival, 53), Jermaine Grandison (Dominic Smith, 37), Liam Lawrence (C), James Collins, Sullay Kaikai, Junior Brown, Anthony Gerrard, Scott Vernon, Abu Ogogo, Tyrone Barnett (Ian Black).
UNUSED SUBS: Callum Burton (GK), Ian Black, Shaun Whalley, Liam McAlinden, Jordan Clark.
BOOKED: Lawrence (72), Knight-Percival (82).
GOALS: Ogogo (90+2).
GRIMSBY TOWN LINE-UP: James McKeown (GK); Richard Tait, Josh Gowling, Craig Disley (C), Padraig Amond, Andy Monkhouse, Craig Clay, Jon-Paul Pittman (Omar Bogle, 23), Nathan Arnold, Aristote Nsiala, Conor Townsend.
UNUSED SUBS: Gregor Robertson, Scott Brown, Shaun Pearson, Andy Warrington, Conor Henderson, James Alabi.
BOOKED: Gowling (39).
REFEREE: Dean Whitestone
ASSISTANTS: Ian Smedley & Michael Denton
FOURTH OFFICIAL: Richard Martin
ATTENDANCE: 2,730 (286)