A goal in either half saw Clyde end Berwick Rangers' five-game unbeaten run in the Scottish Third Division.
Berwick went into the game at Shielfield Park looking to consolidate their play-off position, while Clyde were coming off the back of a goalless draw to league leaders Annan Athletic.
The home side created the first clear chance through top scorer Darren Gribben, whose well-struck shot was palmed away.
It was Cylde who did take the lead, and it was from the penalty spot in the 25th minute.
Goalkeeper Jamie Barclay fouled Jordan White leaving John Sweeney to step up and smash the ball home.
The game was keenly contested with the referee dishing out seven yellow cards.
Ross Gray had a chance to grab an equaliser in the second half but he shot tamely when well placed.
The Bully Wee made the points safe in the 86th minute when Liam Cusack drilled the ball home from close range.
Berwick: Barclay, Elliot Smith, McLean, Townsley, Deland (Damon Gray 78), Notman, Currie, McDonald, Noble, Gribben (Lavery 64), Ross Gray. Subs Not Used: Wood, Greenhill, Thompson.
Booked: Elliot Smith, Currie, McDonald, Deland.
Clyde: A Trialist, Gray, B Trialist, McQueen, Sharp, Hay, Neill, Scullion, Sweeney, White (Oliver 83), Cusack (Irvine 89). Subs Not Used: McCue, Fitzpatrick, Archdeacon.
Booked: McQueen, Sweeney, Hay.
Goals: Sweeney 25 pen, Cusack 86.
Ref: David Somers