Watford are at Wembley and one match away from promotion to the Premier League. The incredible story of how they got there will go down in football folklore.

With the Hornets winning 2-1 and the semi-final locked at 2-2 on aggregate, extra-time looked inevitable when referee Michael Oliver awarded Leicester City a soft penalty. As with the 2-1 defeat to Leeds United that ended Watford’s automatic promotion hopes, it looked like Gianfranco Zola’s men would suffer last-gasp heartbreak again. But what followed in the next 20 seconds was frankly unbelievable.

Manuel Almunia not only saved Anthony Knockaert’s spot-kick but reacted superbly to keep up the follow-up as well. The ball was cleared to the right side of the pitch where Ikechi Anya found Fernando Forestieri, his cross was nodded down by Jonathan Hogg and Troy Deeney blasted it into the net to secure his side’s place in the Championship play-off final where they will play either Crystal Palace or Brighton & Hove Albion on Monday, May 27.

It felt an age ago at the time but the manner in which Watford had got themselves in the position to secure a 3-1 second-leg victory following Thursday's 1-0 defeat should not be overlooked - and in particular the contribution of Matej Vydra.

The Hornets' top scorer had not scored in his previous 13 appearances and there was some surprise that he was chosen to start, and not Fernando Forestieri.

However, the Czech international justified Zola's faith within 15 minutes of the match getting underway, scoring with a sensational left-footed volley from an acute angle on the left side of the area to make the tie level on aggregate.

Within four minutes though, the Foxes were level on the day and had the upper hand again as Dave Nugent got free in the area to head in a corner.

Watford though, continued to plug away and they levelled again on aggregate when Deeney and Vydra combined for the latter to slot the ball beyond Kasper Schmeichel to make it 2-1 with his second of the afternoon.

Extra-time began to look increasingly inevitable though, until the football gods decided to conjure up an astonishing climax to the game that, even now, defies belief.

There were a few surprises as Zola made three changes from Thursday’s first leg at the King Power Stadium.

Most fans were probably expecting Fitz Hall and Forestieri to start but both had to settle for places on the bench as the Hornets boss left his defence unchanged and kept faith with Vydra, despite his goalless run stretching to a 13th match in the 1-0 defeat.

There was no surprise that Deeney returned from his one-match ban to replace Alex Geijo up front, Cristian Battocchio was preferred to Hogg in the midfield engine room and Matthew Briggs came in for Daniel Pudil on the left.

Nigel Pearson decided to leave well alone with his team holding the slender advantage and named an unchanged starting line-up.

There was a change with the officials though, as Phil Dowd, who was meant to be in charge, was replaced by another Premier League referee in Oliver.

The Hornets started confidently, enjoying some good early possession and they nearly enjoyed their first opening in the fourth minute when Marco Cassetti floated a lovely pass over the top looking for Deeney, but Wes Morgan read it and was able to head away from the edge of his own penalty area.

Leicester’s response was to force four corners in succession but the Hornets held strong and so nearly got back on terms in the seventh minute.

Lloyd Doyley side-stepped Lloyd Dyer to bring the ball out of defence before feeding Nathaniel Chalobah, who played it forward to Deeney. He then waited for Vydra to make a run off the shoulder of Ritchie de Laet before slipping a perfectly-weighted pass through the Foxes defence and the Hornets’ 20-goal striker took it first time left-footed but placed his finish agonisingly wide of Schmeichel’s left-hand post.

There wasn’t a lot the Leicester keeper could have done about that shot had it been inside his upright but soon after Schmeichel was having to plunge low to his right to keep out a superbly-struck right-footed drive from Deeney from the edge of the 18-yard box.

However, the Hornets didn’t have long to wait to get back on terms on aggregate when Vydra’s long wait for a goal was ended by a moment of instinctive brilliance.

There didn’t appear to be too much on at first when Cassetti lofted a pass down the inside left channel and into the area but with a defender goal-side and the angle very much against, the Czech international spun and struck a stunning left-footed volley on the turn that gave Schmeichel no chance as it flashed past him to give the Hornets the lead to level up the semi-final.

But parity in the tie was to last just four minutes.

A sliced Cassetti clearance gave Leicester their sixth corner of the match and when the set piece was taken from the left, Nugent pulled away from Doyley at the far post to head down and beyond Almunia to follow up his winner on Thursday with another goal to make it 1-1 and give his side the upper hand again.

It was the striker’s eighth goal in 11 games against the Hornets and soon after the visitors had another opening when Dyer laid the ball across from the left to Knockaert, but he fired over with a first-time effort.

The equaliser didn’t appear to unduly affect Watford though, but they had to wait until the 30th minute for their next effort when Deeney tried to catch Schmeichel out with a shot from 20 yards but the keeper read it and made a catch above his head.

Chris Wood picked up the game’s first yellow card in the 34th minute for playing on after the whistle had blown for offside before Deeney when for an acrobatic finish after Ikechi Anya had stood up a cross from the right side of the area, but the striker’s finish went well wide.

Watford’s domination of possession continued but their next opening didn’t arrive until a minute before the interval when Anya, who clearly had the beating of Jeff Schlupp, nicked the ball past the left-back again before sending over a low cross which Deeney hit first time on the turn but his strike went over.

However, the Hornets had a close call shortly before the half-time whistle when Nugent set Wood away but a marginal offside decision prevented the striker from having a one-on-one opportunity against Almunia.

Zola’s men were soon back on the front foot after the restart, with Anya crossing from the right and the ball was partially headed clear to Cassetti, who powered the rebound high and wide from 25 yards.

Leicester’s first opportunity of the second period came when Almen Abdi was penalised for a foul on Wood around 25 yards out in a central position but Knockaert was unable to make the most of the set piece, curling it a yard or so over Almunia’s goal.

Back came the Hornets though, with Battocchio showing some lovely close footwork on the edge of the box to get away from two opponents before striking a right-footed shot that was deflected narrowly wide of Schmeichel’s right-hand post.

Watford might have had some joy from Abdi’s resultant corner had someone in yellow gambled in the six-yard areas as the ball was allowed to bounce right through the heart of the Foxes’ box.

Instead, the end-to-end nature of the early second-half exchanges continued as de Laet got away from Briggs on the right side of the area before sending over a cross which Wood had to back track to get to. Consequently, his header lacked power and Almunia was able to drop to the floor to make a comfortable save.

But the goal Watford craved so nearly arrived in the 56th minute when Vydra found Briggs on the left. The wing-back side-stepped his man with ease to get into the area before laying the ball across to Vydra, who in turn tapped it to Abdi. His right-footed effort looked destined for the far corner but the slightest of deflections just took it wide.

Pearson made the game’s first change in the 61st minute and it was a repeat of Thursday, with Harry Kane coming on for Wood. Zola rapidly followed suit as Doyley made way for Forestieri.

But within a minute of entering the fray, the Argentine was on the pitch to see his side take the lead as Vydra confirmed he was right back on song.

Watford built from the right with Vydra initially looking like he might feed Forestieri, who was on the left. However, he instead fed Deeney, who returned the ball to Vydra and he slotted it past Schmeichel to make it 2-1 on the day and 2-2 on aggregate.

Danny Drinkwater came on for Dyer before the game had restarted and then Cassetti was booked for a lunging challenge on Kane. However, the substitute’s effort from the resultant free-kick was woeful as it cleared the bar by yards.

Watford were now pouring forward in waves and Battocchio was the next to try his luck, hitting a right-footed drive from the left angle of the area but Schmeichel was able to save it at the second attempt as Deeney closed in.

The Hornets still had to be careful though, and when Nugent was fouled on the edge of the area an even better free-kick opportunity presented itself. But the Leicester striker was unable to get his attempt up and down quickly enough and it went narrowly over the bar.

Kane fired at Almunia soon after as the home side got ragged at the back for a few minutes. But Anya then won a corner and Abdi’s set piece from the right ended with Forestieri hitting a piledriver across goal and wide.

Watford thought they had got the all-important third goal when Deeney slotted the ball through Schmeichel’s legs after he had been released by Vydra but the Rookery’s wild celebrations were cut short by a linesman’s flag.

Forestieri had a shot from outside the area blocked behind for a corner, Cassetti headed the resultant corner down and wide and then Battocchio made way for Hogg with 11 minutes remaining.

The Hornets continued in the ascendency as the game entered the last five minutes of normal time and additional 30 minutes looked an increasing probability. To add to the tension, there was a lengthy delay in the game in the final stages when the outstanding Joel Ekstrand made a superb challenge on the edge of his area but got a kick in the head from Knockaert for his troubles. The Swede needed a quite lengthy spell of treatment, during which the fourth official signalled there would be a minimum of four additional minutes, but he was able to continue.

It was no surprise that more was in fact played and in the sixth minute of additional time it was heart in mouths time when Nugent crossed from the right but Kane wasn’t able to get his shot away. But that was just the prelude for the most incredible spell of drama arguably ever witnessed at Vicarage Road.

It began when Cassetti got the wrong side of Knockaert in the area and as the Hornets defender tried to get back, the Leicester striker went down rather easily but the referee pointed to the spot. It looked like Watford’s promotion dream was over but nobody told Almunia.

Knockaert took responsibility for the penalty but struck it too centrally and the Hornets’ keeper not only saved it with his legs but reacted superbly to block the follow up as well. The ball was hacked clear to the right side of the pitch where Anya ran at Schlupp for one last time before feeding Forestieri. He stood up a cross to the far post, Hogg showed superb awareness to cushion a header down and Deeney powered through to rifle a right-footed shot into the net and send the Hornets to Wembley.

Watford’s goal scorer immediately pulled off his shirt and raced to the Main Stand where the players’ family and friends were sitting before the inevitable pitch invasion ensued.

It took three to four minutes to clear the playing surface before play could restart but all that was left was for Watford to survive one last ball pumped into the area before Oliver blew the whistle for one last time and the celebrations really began.

Watford: Almunia; Doyley (Forestieri 65), Ekstrand, Cassetti; Anya, Abdi, Chalobah, Battocchio (Hogg 79), Briggs; Deeney, Vydra. Not used: Eustace, Hall, Pudil, Bond and Geijo.

Leicester City: Schmeichel; de Laet, Morgan, Keane, Schlupp; James, King; Knockaert, Nugent, Dyer (Drinkwater 66); Wood (Kane 61) Not used: Konchesky, Marshall, Vardy, Logan and Moore.

Bookings: Wood for dissent (34); Cassetti for a foul on Kane (69).

Attendance: 16,142 (2,206 away).

Referee: Michael Oliver.