Second Division promotion hopefuls Raith kept the pressure on leaders Ross County with a comprehensive victory.
The hosts took the lead in the 32nd-minute when Mark Campbell headed home Robert Sloan's corner.
Sloan provided an assist for the second goal when his diagonal pass was glanced past Peter Logan by Steve Hislop.
Substitute Graham Weir sealed victory when he headed home Sloan's corner with one minute late on. Brian Fairbairn was sent off to compound Berwick's misery.
Raith: Renton, Wilson, Dingwall, Campbell, Andrews, Davidson (Winter 45), Sloan, Henderson, Hislop, Goodwillie (Weir 73), David Templeton (Borris 84). Subs Not Used: Tod, Fahey.
Goals: Campbell 34, Hislop 69, Weir 83.
Berwick: Logan, McLeish, McGroaty, Horn (A Trialist 72), Jordan Smith, Thomson, Fairbairn, Ayrre, Howat, Diack, Greenhill (McLean 84). Subs Not Used: Mark Stevenson, Coult, Flockhart.
Sent Off: Fairbairn (90).
Booked: Jordan Smith, Diack.
Ref: S O'Reilly