Chris Porter struck two late goals as Sheffield United beat Nottingham Forest 3-1 to set up a possible all-Sheffield FA Cup quarter-final.
Porter kept his cool to convert a 90th-minute penalty and then netted again two minutes later to settle the fifth-round tie at Bramall Lane on Sunday as United came from behind to claim another FA Cup scalp.
Having already dumped out Fulham and Aston Villa, United manager Nigel Clough will savour this victory over his former club and counterpart Billy Davies, with no love lost between the duo.
Jamie Paterson had headed Forest into a 28th-minute lead, but United - the lowest-ranked team left in the competition - hit back through Conor Coady after the break following a shocking Dorus de Vries error.
A replay at the City Ground looked on the cards before Porter's late double proved decisive and sent United through to the last eight, where the League One strugglers will play host to either Sheffield Wednesday or Charlton Athletic.
The hosts did not seem overawed by their Championship opposition and had a chance to take a 12th-minute lead when John Brayford cut in from the left, but struck straight at De Vries.
A spell of Forest pressure in the 20th minute ended with Simon Cox appearing to be felled by Harry Maguire inside the penalty area, but Forest's surprisingly half-hearted penalty appeals were waved away.
Forest controlled possession, but United were looking dangerous on the break and Jose Baxter wasted a great chance on 25 minutes, hitting a tame shot straight at De Vries.
United were made to pay for their profligacy three minutes later when Andy Reid crossed from the left and Paterson did brilliantly to steer the ball across Mark Howard and in at the far post.
Given the two clubs' respective league positions, United might have been expected to crumble, but the home side continued to threaten and wasted another good opportunity when Stefan Scougall's weak shot was saved after he latched onto Baxter's throughball.
If the United players needed any further motivation at half-time, the news from the draw of a potential quarter-final tie with Wednesday should have done the trick.
And Clough's men did seem to return from the dressing room with renewed vigour, putting Forest on the back foot and forcing two corners in quick succession with Maguire's attempt deflected over before Scougall's half-volley was well-held by De Vries.
United continued to press and, with clear cut chances hard to come by, got a huge slice of luck when De Vries spilled a routine Brayford cross to present Coady with an open goal and the youngster made no mistake.
The tie looked to be heading for a replay, but Greg Halford was penalised for handball inside the area on 90 minutes to give substitute Porter the chance to win the game from the penalty spot.
The former Derby County man converted easily and, as Forest went in search of an equaliser, United hit them on the break, Porter finishing off Jamie Murphy's right-wing cross to seal a famous victory.
|Coach: N. Clough|
for J. Baxter 86'
for R. Harris 90+3'
for C. Coady 90+1'
|West Ham 3 Lusitans 0: Sakho nets twice at start of Europa League journey|
|Holebas makes Watford move|
|Milan secure Adriano signing|
|Peru v Paraguay: Diaz counts cost of semi-final loss|
|Bastia hit out at reports of extra debt|
|Hernandez has successful surgery|
|Odemwingie signs one-year Stoke extension|
|Uth signs for Hoffenheim|
|Henen seals Everton return|
|Cattermole pens long-term Sunderland deal|
|United States v Guatemala: Klinsmann backs Dempsey ahead of Gold Cup warm-up|
|West Ham working on Jenkinson return - Gold|
|Milan agree deal for Bacca|
|Real buy back Vazquez from Espanyol|
|Richards leaves Swansea for Fulham|
|McShane signs for Reading|
|Giggs tells youngsters to seize US chance|
|Hammond pens Leicester extension|
|Only Schweinsteiger can decide Bayern future - Guardiola|
|Cech plans to play until he´s 40|
|Montoya arrives in Milan ahead of Inter move|
|Hernandez out of Gold Cup|
|US asks Switzerland to extradite seven FIFA officials|
|MLS Preview: Sounders seek momentum switch|
|Mexico 0 Honduras 0: Hernandez injury sours friendly|
|Hernandez taken to hospital|
|Garay in doubt for Copa America final|
|Wambach: USA peaking for World Cup final|
|Bassett ´an absolute hero´ despite own goal - Sampson|
|Japan 2 England 1: Late own goal breaks English hearts|
|Salvo quits as Valencia president|
|Costa not Ribery cover - Bayern director Sammer|
|Chile, Argentina deserve final spots - Mena|
|Ramos keen on United switch - Calderon|
|B36 1 The New Saints 2: Wilde leaves it late to secure advantage|
|Sevilla agree deal for Rami|
|Celtic snap up United teenager Janko|
|Beauvue passes Lyon medical|
|Roma bring in Falque|
|Coates completes permanent Sunderland switch|
|Vallecano to make charity donations from shirt sales|
|Angella commits to Watford|
|Gundogan pens new Dortmund deal|
|Juve reject €80million Barca offer for Pogba, says Marotta|
|Ruiz seals permanent Villarreal move|
|Mourinho respects Cech´s decision to quit Chelsea|
|Claridge excited by potential Pearson successors|
|Miranda completes Inter switch|
|Blind takes over as Netherlands coach|
|Mourinho: Premier League tougher to win than ever|
|Hamburg make Holtby move permanent|
|Southampton terminate Osvaldo contract|
|BREAKING NEWS: Swansea swoop for Eder|
|Abbiati extends Milan stay|
|Cruyff: Barcelona have lost their values|
|Vydra seals Watford move|
|Ambitious Clyne targets trophy haul with Liverpool|
|Claridge: Off-field incidents cost Pearson his job|
|Clyne becomes Liverpool´s sixth close-season signing|
|Imbula leaves Marseille for Porto|
|FIFA chief Blatter challenges critics to prove corruption claims|
|Distin joins Bournemouth|
|Bayern seal Costa deal|
|Arsenal confirm Diaby departure|
|Blatter to miss Women´s World Cup final|
|Bogdan sets sights on being Liverpool number one|
|Danilo eager to get started at Real Madrid|
|Leicester´s Wood joins Leeds|
|Porto confirm Atletico move for Martinez|
|Lloyd: Repetition key to netting penalty|
|Sheffield Wednesday job a ´dream´ for Carvalhal|
|´We played a complete game´ - Messi|
|Diaz upbeat despite heavy Copa loss to Argentina|
|Martino lauds Messi for selfless performance|
|Viviani makes surprise Verona switch|
|Estonian team wins cup match 31-0|
|No meeting with Arsenal has occurred - Vidal´s agent|
|United States 2 Germany 0: Ellis´ team reach World Cup final|
|Argentina 6 Paraguay 1: Messi leads Martino´s men to Copa final|
|UEFA Europa League Review: FK Zeljeznicar and FC Dacia Chisinau open with wins|
|UEFA Champions League Review: FC Pyunik make winning start|