Kyle Miller's injury-time winner for Cowdenbeath sank Clyde 2-1.
Clyde took the lead when summer signing David Gray lashed the ball into the top right-hand corner for his first goal for the club.
But six minutes into the second half the Blue Brazil drew level, Lewis Milne firing in off the crossbar with a cracker from 25 yards.
Craig Johnston went close for Cowdenbeath midway through the second half when he drilled narrowly wide from inside the area.
But Miller won it in the first minute of stoppage time when he headed in a cross from Sean Higgins.