Berwick opened the scoring after six minutes when Kevin Haynes volleyed home a cross from Kevin McLeish.
Montrose hit back, and after 11 minutes Calum Watson beat a defender and fired a shot inches wide from the edge of the box.
After 14 minutes Montrose's Darren Kelly was short with a headed pass-back allowing Sean Paliczka in, but Stephen Fraser made a fine clearance to prevent a certain goal.
In the 31st minute a fierce drive from Ian Little forced a great save from Sandy Wood.
Two minutes into the second half, a Mark Cowan header from a corner struck the top of the Montrose cross bar.
Aftern 50 minutes a shot on the turn from Watson was tipped over by Gary O'Connor. Three minutes later a Cowan header was cleared by Barry Donnachie with Berwick claiming that the ball was over the line.
Montrose equalised after 57 minutes when Watson had a shot blocked and Martyn Fotheringham followed up to score.
Berwick regained the lead in the 63rd minute when Haynes scored with a header from a McLeish corner.
Montrose were reduced to 10 men after 74 minutes when Fotheringham collected a second booking for a foul on Danny Swanson.
.