Aye, the hosts have arrived.

Max Kucheriavyi and Stephen McGinn have two dangerous shots blocked. Huge roar of encouragement from the home crowd.

Better from Falkirk.

A super cross from Callumn Morrison is met by the knee of Max Kucheriavyi. Not far wide.

Dipo Akinyemi looks sharp. The Ayr danger man has made a promising start as he wins a corner.

Again, the set piece comes to nothing.

Stoppage in play as a steward has to come onto the pitch to pick off a pyrotechnic.

Ayr corner. They've started well.

Reece McAlear takes. Comes to nothing.

Dipo Akinyemi's first involvement.

The Ayr striker drills in a cross to Reece McAlear, who heads narrowly wide.

Not easy to see the players through this smoke...

Here we go...

Crackin' atmosphere at a smoky Falkirk Stadium.

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Victory for favourites Ayr will see them reach their first Scottish Cup semi-final in 21 years.

A 3-0 defeat to Celtic that day prevented tonight's visitors progressing to the 2002 final.

Falkirk's was far more recent. In 2015, Peter Houston's side made it all the way to final after beating Hibernian in the last four.

But Houston's men fell at the last hurdle, losing to Inverness CT at Hampden.

Ayr Utd manager Lee Bullen tells BBC Scotland: "Aidan [McAdams] has played in all the cup games and he's one of the reasons we've come this far. He's made some vital saves and he deserves the opportunity.

"I have fond memories of being at Falkirk, as a player and coach, and I have great respect for John McGlynn and his staff. We'll have to be on our toes tonight."

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That big support McGlynn mentions is expected to be over 5,000.

Could be a rowdy one...

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Falkirk boss John McGlynn tells BBC Scotland: "We've picked the team we feel will win the game. Three tactical changes - we feel to win the game we have to do something a bit different and hopefully that will come off.

"This is a one-off, this could be extra-time, penalties. I'm not anticipating a lot in it, I think it'll be tight. Ayr are a very good side. It'll be a tasty game I would suggest.

"The players will be doing their utmost to get to Hampden. We've got a big support tonight which just shows the potential of the football club."

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Ayr boss Lee Bullen hailed Dipo Akinyemi as the "find of the season" last Wednesday. No wonder.

The 25-year-old scored his 20th goal of the campaign in Ayr's midweek win at Morton.

John McGlynn's defence will have to keep a close eye on the striker, who also has 10 assists this term, totalling a mightily impressive tally of 30 goal contributions in 34 games.

"He has a very big future in front of him," Bullen added. "We're just delighted with the impact he's having here."

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Leanne Crichton
Ex-Scotland international on BBC Sportscene

Ayr had a good result against Morton last week, apart from that they've been fairly inconsistent. But we know what the cup brings and it brings the opportunity to switch off from the league.

Ayr travel to Falkirk off the back of a 3-1 win at Morton, but they've been on a stuttering run of form.

Four wins in their last 12 games leaves them fourth in the Championship, eight points off leaders Queen's Park.

Falkirk are also eight points off the pace in League 1, despite sitting second in the table.

Defeat to league leaders Dunfermline last Tuesday ended an impressive 11-game unbeaten run, which included 10 wins and a draw.

Back to normal tonight.

From 19:30 GMT you can catch the build-up on the BBC Scotland channel followed by full match coverage at Falkirk Stadium.

Steven Thompson is the host, with Leanne Crichton and Marvin Bartley on punditry.

You'll also be able to click play at the top of this page if you want the best of both.

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Tonight. Straight after this game.

You'll be able to watch it unfold live on the BBC Scotland channel. We'll also keep you updated right here.

Don't imagine it'll be anything like the Scottish Amateur Cup draw that was kicking about Twitter the other day...

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So who's already in the semi-final hat?

Inverness CT booked the first spot on Friday, coming back from a goal down to stun top-flight Kilmarnock.

There were no shocks on Saturday or Sunday, though, as Celtic strolled past Hearts at Tynecastle before Old Firm rivals Rangers eased past second-tier Raith Rovers yesterday.

Catch all the best bits from the three ties by clicking the big play buttons below.

John McGlynn makes three changes to his Falkirk side after last Tuesday's defeat at Dunfermline.

Out go Sean Mackie, Kai Kennedy and Gary Oliver as Brad McKay, Leon McCann and Matthew Wright, making his first start for the club, all come in.

As for visitors Ayr, it's just one switch from the line-up that started last week's 3-1 win at Morton.

That change comes in goal as Charlie Albinson makes way for Aidan McAdams.

Image source, SNS

Falkirk: Kinnear, Rowe, McGinn, Henderson, Donaldson, C Morrison, Nesbitt, McCann, Wright, McKay, Kucheriavyi.

Substitutes: PJ Morrison, Williamson, Yeats, McGuffie, Oliver, Burrell, Lawal, Mackie, Kennedy.

Ayr Utd: McAdams, Reading, McGinty, Musonda, Houston, Ashford, McAlear, Dempsey, McKenzie, Maguire, Akinyemi.

Substitutes: Albinson, Murdoch, Bilham, Mitchell-Lawson, Kirk, Smith, Bryden, McAllister, Tomlinson.