Hibernian took their fans from the depths of despair to delirium as a stunning extra-time strike from Leigh Griffiths sent them into the William Hill Scottish Cup final after a young Falkirk side had taken a three-goal lead inside half an hour.

Griffiths arrowed a 25-yard strike into the top corner with five minutes remaining of a classic encounter which gives Hibs the chance to atone for their 5-1 final defeat by Edinburgh rivals Hearts last season.

Goals from teenagers Craig Sibbald and Jay Fulton plus 21-year-old Blair Alston had given Gary Holt the best possible start to a managerial career.

But it was a teenager in green who inspired one of the great Hampden comebacks as Alex Harris scored from 25 yards in the 51st minute before Hibs put their Irn-Bru First Division opponents under intense pressure.

Griffiths missed penalty before netting and Eoin Doyle sent the game into extra-time with a long-range effort.

A week after admitting Hibernian's season had been a failure because of their failure to make the top six of the Clydesdale Bank Premier League, manager Pat Fenlon must have been fearing for his job at half-time.

Fenlon recalled Paul Cairney and Scott Robertson in midfield but neither saw second-half action and Hibs only started playing after he changed from his favoured 4-5-1 formation.

But his side turned the game around with lifelong Hibs fan Griffiths scoring his second semi-final winner in two years, and his 25th goal of the season.

Hibs were behind in the sixth minute after Alston made the ball his 25 yards out and played Lyle Taylor into the right channel. The striker cut the ball back and Sibbald showed composure beyond his 17 years to guide a left-footed shot into the bottom corner.

Robertson missed a glorious chance to equalise when he completely miscued his volley after Griffiths found him unmarked 10 yards out, and Falkirk doubled their lead in the 18th minute.

Sibbald sent in a high free-kick and Falkirk were first to every ball. Johnny Flynn won the initial header and Conor McGrandles hooked the ball into the goalmouth where 19-year-old Fulton got in front of Cairney to guide a diving header into the bottom corner.

Hibs looked shell-shocked and their fans booed them as they passed the ball without purpose in their own half, although Harris forced a save from Michael McGovern when his volley looped towards the top corner.

But Falkirk went further ahead a minute later after the Hibs defence completely opened up when Alston won a challenge with Tim Clancy 30 yards out. The ricochet sent Taylor clean through and although Ben Williams got down to save his effort, Alston tapped home the rebound.

Dozens of Hibs fans headed for the exit to avoid another Hampden humiliation while some tried to get close to the technical area to vent their fury at Fenlon.

The Hibs manager took off Robertson for Danny Handling but Hibs could not create a chance before the break and Taylor had a great chance when Stewart Murdoch's wonderful long pass sent him clear, but McGovern got down to block.

Hibs were roundly booed off at the half-time whistle but their fans cheered them back out with Doyle on for Cairney in a new 4-4-2 formation.

Hibs belatedly burst into life when Harris played a one-two with Doyle and fired a volley which McGovern pushed on to the post.

Hibs should have had a penalty seconds later when Murdoch's clumsy challenge brought down Clancy but Harris soon got the early second-half goal Hibs were desperate for.

The 18-year-old cut inside and fired a right-footed shot that took a slight deflection off the head of Darren Dods and nestled in the top corner despite McGovern getting both hands to it.

Handling and Doyle both failed to make the most of good chances and Hibs fans, who were now roaring their team on, might have suspected it was not their day when Griffiths sent a free header over and then passed up a chance to shoot from Doyle's cross.

Those suspicions were reinforced when the on-loan Wolves striker missed a 72nd-minute penalty after Murdoch had clipped Handling. McGovern made a great double save as he also stopped Doyle's follow-up.

But Griffiths rediscovered his goalscoring touch five minutes later when he guided the ball home from seven yards after Harris had got in behind Falkirk again.

Falkirk, with a fifth teenager on in the shape of substitute Thomas Grant, could not withstand the tide and Doyle equalised in the 83rd minute when he ran from the centre circle before firing a 25-yard strike into the bottom corner.

Dods was fortunate to get away with a clumsy penalty-box aerial challenge which felled Griffiths before Iain Brines blew for full-time in his last act before being replaced by fourth official John Beaton because of injury.

Hibs remained on top and Griffiths had a goal disallowed for a contentious offside decision following Doyle's first-time pass in the first period.

A drained Falkirk side tried to hold on but Griffiths came up with the latest wonder goal of his spectacular personal season and Williams made a brilliant late save from Taylor to send Hibs through.