Watch FULL MATCH REPLAYS & more via MUTV 24/7 on beIN SPORTS | Sign up for our 7-day free trial | AU | NZ

Sky Blues captain Ben Sheaf sent the crucial spot-kick over the crossbar leaving Rasmus Hojlund to win it for the Red Devils, but the game will be remembered for three goals in the final 20 minutes by the EFL Championship side as it recovered from 3-0 down to force extra-time.

Erik ten Hag’s team was three up and cruising through to the 26 May (AEST) final after goals from Scott McTominay, Harry Maguire and Bruno Fernandes put it on course for what at that stage looked a routine win.

But Mark Robins’ side, which is eighth in English football's second tier, roared back with a recovery that almost defied belief.

First Ellis Simms converted a cross at the near post on 70 minutes to make it 3-1, then Callum O’Hare’s strike looped in off Aaron Wan-Bissaka to rattle United and spark a frantic finish.

Thereafter chaos reigned among Ten Hag’s defence as it clung on perilously to the lead, until three minutes into stoppage-time Wan-Bissaka handled inside the box, giving Haji Wright the chance to write one of the great FA Cup stories from the penalty spot.

Sending Onana the wrong way, he coolly took the game to extra-time.

Coventry thought it had secured a stunning win when Victor Torp turned Wright’s cross into the net in the final minute of extra-time before Coventry’s brief joy was extinguished a VAR review for offside.

A stunning cup tie was ultimately settled by penalties, Sheaf firing into the United fans as Coventry fell short by a whisker.

United had the first chance after six minutes. Onana hoofed the ball towards the edge of the Coventry box where Fernandes was waiting to nod it into the path of Alejandro Garnacho, who stretched but could only guide it wide.

Marcus Rashford was next to go close, taking Casemiro’s raking 60-yard pass brilliantly in his stride before clipping a shot wide of Bradley Collins’s post.

Coventry was struggling to emerge from its own half and a goal for United seemed a matter of time.

It arrived after 23 minutes, Garnacho receiving the ball wide on the right and feeding the overlapping Diogo Dalot. His low ball found McTominay, stealing away from his defender to knock in his 10th goal of the season from virtually on the line.

Coventry finally threatened five minutes before half-time, Josh Eccles getting free on the right of the penalty area and crossing dangerously into the six-yard box.

It looked destined for the foot of Simms, before Dalot bravely intervened to clear for United with a lunging tackle.

Rashford drew a fine save from Collins moments before the break and at that moment it looked like Coventry would see out the half only a goal behind.

But its defence could not hold and from the resulting corner Maguire evaded the attentions of everybody in sky blue and planted a header into the bottom corner for 2-0.

The fight looked gone from Coventry on the hour mark when Fernandes scored via a deflection to make it three.

Joel Latibeaudiere initially derailed Rashford as he sought space to shoot but the ball slithered out of the defender’s control and arrived at the feet of United’s captain who lashed it into the net via the unfortunate Bobby Thomas.

The tie looked over but from somewhere Coventry summoned heroic resolve. Simms ignited a flicker of hope, guiding Fabio Tavares’s low cross beyond Onana, then O’Hare’s strike hit Wan-Bissaka and sailed over the goalkeeper for 3-2.

Haji’s penalty sparked joy amongst Sky Blues fans behind the goal as under-pressure United Ten Hag watched on forlornly.

Fernandes and Simms hit the underside of the same crossbar in either period of extra-time, then Torp thought he had won it in added time before VAR’s intervention.

After Casemiro and O’Hare saw their penalties saved in the shootout, it fell to Hojlund to hit the winning kick as United breathed a huge sigh of relief, progressing to the final where it will meet fierce cross-town rival Manchester City.