The Republic of Ireland's dream of reaching the World Cup finals for the first time in 24 years was shattered by the Czech Republic, who won 4-3 on penalties at the end of an incident-packed play-off semi-final in Prague.

After Finn Azaz and Alan Browne had shootout efforts saved, Czech Republic forward Jan Kliment fired the decisive kick past Caoimhin Kelleher to break Irish hearts and send the hosts into Tuesday's play-off final against Denmark.

The Republic of Ireland had briefly been in the driving seat as Troy Parrott's penalty and Czech goalkeeper Matej Kovar's own goal put Heimir Hallgrimsson's side two up after 23 minutes.

However, the hosts hit back quickly through Patrik Schick, who converted emphatically from the spot after Ryan Manning's foul on Czech captain Ladislav Krejci.

While the Irish looked comfortable for large spells in the second half and nearly restored their two-goal led when Jayson Molumby struck a post, Krejci marked the first game of his captaincy with an 86th-minute header to force extra time.

In the shootout, Parrott, Krejci, Adam Idah, Tomas Soucek and Robbie Brady all scored before Kelleher's save from Mojmir Chytil raised hopes of an Irish win.

But after Kovar denied Azaz and Browne either side of Schick's successful attempt, Kliment blasted home to send Fortuna Arena into raptures and leave the Irish players devastated.

There were worrying scenes in the second period of extra time when Sammie Szmodics was knocked unconscious following an aerial collision shortly after he replaced Molumby, with Hallgrimsson later confirming he was conscious in hospital.

This is a remarkable victory for the Czech Republic when framed by the context of their turbulent build-up.

After a disappointing qualifying campaign that included a 5-1 hammering by Croatia and a shock loss to the Faroe Islands that cost head coach Ivan Hasek his job, Soucek was stripped of the captaincy before Miroslav Koubek's appointment.

One of the 74-year-old's first big decisions was to drop Soucek to the bench for Thursday's game, although he introduced the West Ham midfielder at the start of the second half.

That was after a largely listless 45 minutes from the hosts when they rarely threatened the Republic of Ireland, before Ryan Manning pulled Krejci's shirt and allowed Schick to convert from the spot.

Neither side dominated the second half but the hosts denied the Republic of Ireland a famous win when Krejci headed Michal Sadilek's free-kick low into Kelleher's net to give them a lifeline.

The Czechs last qualified for the World Cup in 2006, but they will bid to end a 20-year wait with victory on Tuesday over Denmark, who comfortably beat North Macedonia 4-0 to advance.

Much of this is familiar territory for the Republic of Ireland. Defeat in Prague marks the country's sixth successive failed bid to reach the World Cup, while they are no strangers to penalty pain.

Their last shootout defeat came against Slovakia in the Euro 2020 play-off semi-final in Bratislava.

That was in an empty stadium, in stark contrast to the ear-splitting noise they had to contend with in Prague.

Hallgrimsson will be deeply frustrated given how his side troubled their hosts for much of the game.

Considering it was his goalscoring heroics that catapulted the Republic of Ireland to this stage, it was appropriate that Parrott struck the first blow.

And like he did for the first of his three goals against Hungary in Budapest, he kept his cool to score from the spot after referee Glenn Nyberg penalised Vladimir Darida's challenge on Nathan Collins following a pitchside monitor review.

Four minutes later, the Irish supporters who sang their hearts out all night greeted a second goal rapturously, but that was as good as it got as missed chances stacked up.

With Collins having hit the bar early on, Molumby cracked the woodwork with a wicked 53rd-minute effort and Parrott had a header tipped away by Kovar before Krejci struck to send the game to extra time.

After a lengthy delay following the injury to Szmodics, neither side found a winner before a dramatic penalty shootout that ended with yet more heartache for the Republic of Ireland.

Hallgrimsson must somehow lift his squad for a meaningless game against North Macedonia in Dublin on Tuesday before watching another World Cup tournament through gritted teeth.