Rangers went into the match on the back of a run which had seen them lose only one of their previous 10 fixtures.
But they were undone by the Angus side, with Gary Fraser scoring the only goal of the game after 43 minutes.
Chris Templeman was the first to show for the home side after four minutes with a shot over the bar.
Darren Lavery then had a shot saved from outside the box by Miller, whilst seconds later, at the other end, Adrian Mallagaray pulled a shot wide.
Berwick keeper Kevin Walker then saved to deny Terry Masson, and he also saved from Kieran McWalter, whilst Fraser shot wide.
But just two minutes before the half-time break Fraser managed to find the target, breaking the deadlock after being set up by Templeman.
In first half injury time Stevie Notman shot wide for Berwick, and it remained 1-0 at the break.
Early in the second half Berwick’s Brian Martin had a shot blocked, whilst Finn Graham had a shot saved by Miller.
As Rangers tried to force their way back into the match, Allan Walker shot wide, whilst Blair Henderson had a shot saved.
Barry Hogg, who replaced Graham, also had a shot saved by Miller, whilst Graham Webster had two efforts for the home side within three minutes, the first of which was saved by Walker, the second of which he headed over the top.
Late in the game Ross Campbell also had a shot saved by Walker, and in injury time Callum Crane shot wide with an effort from outside the box whilst Hogg had another shot saved by Miller.
But Berwick were unable to find a way through and the defeat meant they finished the season in sixth place in the table on 49 points, seven behind fourth, which was the final play-off qualifying spot.
Montrose: Miller, Comrie, Pascazio, Steeves (Clarke 38), Campbell, Webster, McWalter, Masson, Mallagaray, Templeman (Milne 71), Fraser (Ferguson 89).
Berwick Rangers: Walker, Beveridge (Watt 77), Wilson, Fairbairn, Crane, Notman, Graham (Hogg 62), Waler, Martin, Henderson, Lavery.