Billy Sharp’s 94th-minute winner sent Sheffield United through to the Emirates FA Cup Fifth Round and ended non-League Wrexham’s run with a 3-1 win at Bramall Lane.
A pulsating cup tie was decided at the death, as Sharp pounced on a defensive error to curl past Rob Lainton.
The tie had looked set for extra-time after Paul Mullin’s penalty had cancelled out Anel Ahmedhodzic’s opener until Blades legend Sharp produced a clinical finish before Sander Berge sealed the victory with a third in the dying seconds.
The hosts were dominant in the first-half and should have gone in ahead at the break, but James McAtee was unable to slot home when clean through on goal.
Amends were made just five minutes after the break, as Bosnian centre-back Ahmedhodzic rifled home from inside the box.
The Blades’ lead lasted just nine minutes as marksman Mullin converted from the spot after being brought down by goalscorer Ahmedhozic.
Mullin then had a chance to put the National League side ahead with another penalty in the 71st minute but Adam Davies saved superbly to keep the score level.
It proved to be a turning point as the Blades held their nerve to finally defeat their lower league opposition, as Sharp and Berge both netted late on to end two terrific games of cup football.
The upset of the night was at Blundell Park, where League Two Grimsby Town comprehensively knocked-out Championship Luton Town with a 3-0 victory.
Harry Clifton opened the scoring after just nine minutes for the hosts, with the striker converting after being played in by Danilo Orsi-Dadomo.
Provider then turned scorer, as Orsi-Dadomo smashed home from inside the box to double the lead just before the half hour.
And Danny Amos sent Mariners fans into dreamland as he made it three before the break, curling home a stunning free-kick in off the post and sealing a trip to Southampton for Paul Hurst’s side.
There was late drama at Turf Moor, where Nathan Tella’s double sent Burnley through with a 2-1 win against Ipswich Town.
Tella needed just 46 seconds to open the scoring for the Clarets only for George Hirst to equalise just two minutes later.
A game of few chances was then decided in the 95th minute, as Tella grabbed his second to win the tie for Vincent Kompany’s men.
They will welcome Fleetwood Town in the fifth round, after the Cod Army beat Sheffield Wednesday 1-0.
Carlos Mendes Gomes’ strike on the hour was the difference between the two sides, with the winger nodding home at the near post to send his side through to the fifth round for the first time in their history.
On Wednesday night, Fulham held off a late surge from Sunderland to book a fifth round tie against Leeds United.
After Harry Wilson had put his side ahead in the first half, Fulham's advantage doubled when Andreas Pereira netted just before the hour mark.
With less than 15 minutes to go Jack Clarke gave the hosts hope as he pulled one back, though Layvin Kurzawa quickly restored Fulham's two-goal advantage.
Sunderland gave themselves hope when Jewison Bennette scored their second in the 90th minute, though their Premier League opponents held firm to progress.