Two clubs currently from outside the top division go head-to-head for a place at Hampden.
Falkirk are currently rooted in League One, but have beaten Wick Academy, Alloa and Darvel, thereby enjoying their best run in this competition since 2018.
On Tuesday night, the Bairns were involved in a huge top of the table clash as they seek to get out of the third-tier.
However, their automatic promotion hopes suffered a serious blow, beaten 2-0 by Dunfermline, so are now eight points adrift the Pars.
As for Ayr United, they are up to third in the Championship, having beaten Greenock Morton 3-1 in mid-week, with Sam Ashford, Sean McGinty and Dipo Akinyemi haha scoring.
In this competition, the Honest Men have so far dumped out Pollock, Cove Rangers and Elgin, so are on the verge of their first semi-final appearance since 2002.
Will John McGlynn’s men make home advantage count at Falkirk Stadium?