Armagh's Shane McPartlan scores his penalty to level the scores.

Monaghan's Jack McCarron sweeps home his penalty with a fine left-foot strike.

Rian O'Neill scores Armagh's first penalty - low and hard into the corner.

Conor McManus scores the opening penalty for Monaghan.

This will be Armagh's third shootout in 12 months.

There was that Galway defeat in last year's All-Ireland quarter-final and also this year's Ulster final which they lost against Derry.

Will this be third time lucky?

Michael Murphy on GAAGO:

A semi-final is on the line. Who will step up? It's about cool, calm heads now.

Image source, Getty Images

McManus was nerveless there.

Monaghan's All-Ireland survival rested on that kick, but you wouldn't know it with the way he calmly stroked it over.

To penalties we go!

Outrageous scenes at Croke Park as Conor McManus slots a late, late free to bring Monaghan level and send the game to penalties.

Such drama. Such late, late drama.

Beggan goes short and Conor McManus has drawn a foul for another free - in the sixth minute of injury time.

Now another massive moment.

Huge moment as Rory Beggan sizes up a free for Monaghan.

This game could hinge on this kick.

POINT FOR ARMAGH!!!!!!!!!!

Rian O'Neill - what a strike in additional time!!!

The build-up was patient and the strike from O'Neill was clean. Nerveless from their main man.

Can't be much more time left now.

Image source, Getty Images

Three minutes of additional time incoming.

A big chance for Armagh is passed up.

Stefan Campbell did really well to cut inside from the left but his right-foot shot went wide.

Will that prove to be the last chance of the game?

It's 18 years since Armagh last played in an All-Ireland semi-final.

Will that stretch to 19 or are they going to squeeze through to the last last four?

Four minutes remaining. Could be next score wins.

Image source, Inpho

Really not sure what happened there.

A message came up to say 'Hawk-eye data unavailable' so the point is not given. It could, of course, have been that the referee got the message but they were just not able to relay it on the big screen.

That could prove to be a massive talking point.

It remains all square.

A Michael Bannigan is being checked to see if it went inside the post or wide.

As if we needed any extra tension.....

Second period of extra-time underway.

A massive 10 minutes incoming.

Michael Murphy on GAAGO:

It's an arm wrestle. It's very difficult to see anything other than penalties.

Managers Kieran McGeeney and Vinny Corey delivering their messages to their teams.

Will it be sinking in? Will they have any words of wisdom to inspire a win in these last 10 minutes?

Image source, Getty Images

Michael Murphy on GAAGO:

Two neighbouring counties, we're going to see a huge battle here. What an opportunity to get into an All-Ireland semi-final!