Forres led 2-0 until the 83nd minute but it took a late goal from Can-Cans’ leading scorer Lee Fraser to take the points back to Mosset Park.
Broch manager Mark Cowie was deflated after watching his side mount a spirited comeback only to conceded in the 90th minute.
Cowie said: “I thought that there was only going to be one winner. We came back from 2-0 down with just seven minutes left and scored twice to make it 2-2, but I was wrong.
“We had the lion’s share of the game in both halves, although Forres did have a 15-minute spell when goalkeeper Paul Leask kept us in the game with a couple of brilliant saves, but apart from that we had more of the ball.”
Mechanics manager Charlie Rowley said: “The fact Paul Leask won the man of the match award summed it up for me. They were the better team in the second half, but in the first 45 minutes when our spirit, endeavour and work-rate was evident.”
The visitors took a 13th-minute lead when Liam Baxter netted from a Scott Graham corner and Baxter made it 2-0 from the penalty spot in the 63rd minute after he had been brought down in the box by Bryan Hay.
Broch scored two late goals in quick succession, first a stunning 20-yard goal from Ryan Cowie in the 83rd minute and three minutes later Gary Harris scored from close range.
In the final minute Fraser grabbed a dramatic winner when he turned in a Gordon Finlayson free kick.