Paul Ritchie double condemmed Rangers to their second defeat of the season as they failed to topple the league leaders. Berwick had the chance to leap-frog the Fifers and they threatened after six minutes, but an Iain Thomson shot lacked power.
East Fife were awarded a penalty after 15 minutes after Paul Hampshire was hauled down by Jordan Smith. Paul Ritchie coolly sent the keeper the wrong way from the spot.
Berwick were unlucky when Thomas Courts appeared to handle the ball in the box, but the referee waved away their appeals.
Richie grabbed a glorious second goal after 34 minutes when he acrobatically volleyed the ball into the top corner.
Berwick came close with a Thomson effort before Kevin Gordon forced Gary O'Connor into a finger-tip save.
Gordon missed a great chance when he scuffed a chance straight at Gary O'Connor and Berwick tried to hit back. Calvin Shand drove a good effort wide and Tom Britton miscued at the back post as Rangers failed to get a consolation.