Dani Ceballos scored a stoppage-time winner as Arsenal reached the FA Cup semi-finals with a dramatic 2-1 win over Sheffield United.
Nicolas Pepe's first-half penalty appeared set to be the only goal at Bramall Lane, only for a largely forgettable game to explode into life in the closing stages.
Sead Kolasinac's poor clearance struck team-mate Shkodran Mustafi to inadvertently tee up David McGoldrick for an 87th-minute equaliser, seemingly sending the game into extra time.
However, substitute Ceballos beat Dean Henderson with a low shot from a tight angle to secure a July trip to Wembley for Mikel Arteta's side.
Such a wild finish was not in keeping with the rest of the tie. The Gunners had capitalised on Chris Basham's careless clip on Alexandre Lacazette on the edge of the area to take the lead from the spot in the 25th minute.
United – who had an early header from John Lundstram ruled out for offside following a VAR check – huffed and puffed without truly threatening, Basham squandering a glorious chance to atone for his earlier indiscretion when heading Jack Robinson's teasing cross wide at the back post.
Arsenal helped out their opponents, though. McGoldrick scored just his second goal of the season – both of them coming in the FA Cup – as he made the visitors pay for their failure to clear a long throw under little pressure.
Billy Sharp was then denied by Emiliano Martinez but Ceballos made no mistake at the other end, the Spaniard running onto a loose ball before firing home to settle the all-Premier League clash.
What does it mean? Cup run offers hope
The FA Cup could provide a silver lining amid the dark clouds looming over Emirates Stadium.
Arteta has fond memories of the competition too, having lifted the trophy twice during Arsene Wenger's reign. With a route into Europe looking tricky via the league, the season may hinge on their progress.
As for the Blades, they remain stuck in a rut. They at least managed a goal in their fourth outing since the resumption but, while their return to the top flight is a success no matter what happens in the coming weeks, this is not the finish Chris Wilder had planned.
Pepe shows his value
Arsenal's record signing scored the club's first penalty in the FA Cup since his boss netted against Everton in 2014. Pepe is now up to 16 goal involvements in his debut campaign - only Pierre-Emerick Aubameyang (21) has had more in the squad.
Bash in the back
With his back to goal, Lacazette was seemingly going nowhere in particular when the ball was fed into him. However, Basham's eagerness to get close led to contact - it was a soft, needless foul to give away, while his botched diving header in the second half was another moment to forget.
Key Opta facts
- Arsenal have progressed to the semi-finals for the fourth time in seven seasons. It is their 30th appearance at this stage, a record they share with Manchester United.
- Sheffield United have lost three matches in a row in all competitions for only the second time since Chris Wilder's appointment in 2016.
- The Gunners have now won seven of their last 10 matches in all competitions (L3), as many as they managed across the previous 27 matches beforehand (W7 D14 L6).
- Nicolas Pepe's penalty was Arsenal's first FA Cup goal from the spot since Mikel Arteta netted against Everton in a 2013-14 quarter-final tie.
- David McGoldrick has scored two FA Cup goals this season from four shots. However, he is yet to score in 23 Premier League appearances having had 37 attempts.
- Timed at 90:37, Dani Ceballos' goal was Arsenal's latest in the FA Cup since Alexis Sanchez (100:06) against Manchester City in the semi-finals in April 2017.
Arsenal will hope to continue the momentum when they host bottom club Norwich City in Premier League action on Wednesday. United, meanwhile, have an extra day to prepare for their home fixture with Tottenham.