Airdrie United wrapped up a 6-1 aggregate win to set up a promotion play-off final with Stirling Albion.
The visitors passed up three good chances to fight their way back into the tie before Kevin MacDonald's effort crept over the line.
And the Diamonds made sure they would have a chance of staying in Division One after Stephen McKeown's cool finish on 76 minutes.
The same player settled matters with a wonderful strike from long range.
Airdrie Utd: Robertson, Proctor, Lovering, MacDonald (Smyth 71), McKenna, McGowan, Potter, Taylor, Twigg (McKeown 63), Harty, Holmes (McDougall 44). Subs Not Used: Lukaszewski, Hollis.
Goals: MacDonald 40, McKeown 76, 84.
Brechin City: Nelson, Murie (Richard Walker 69), Callaghan, White, Scott Walker, Byers, Steven Ferguson, King, Hampshire (Connolly 46), Russell, Smith (Johnson 53). Subs Not Used: Archibald, Hillcoat.
Booked: Callaghan
Att: 1,298
Ref: M Ritchie