Scott Dalziel scored a brace as Berwick ended Annan's unbeaten start to the season with a thrilling win.
The frontman needed just three minutes to open the scoring as he fired a right-footed shot into the bottom-left corner.
The hosts doubled their advantage when Kenny O'Brien fired low past Kenny Arthur.
The goals continued to flow in the first half.
David Hopkirk scored a screamer to reduce the deficit before Dalziel restored Berwick's two-goal lead with a header from a Dean Hoskins cross.
Ally Love scored the fifth goal of the half from the penalty spot to make it 3-2.
Darren Lavery headed home after more good work by Hoskins just before the hour mark to make the points safe for Berwick.
Berwick: Grant, Jacobs, Dunlop, Stephen Tulloch, Hoskins, Notman, Janczyk, Lee Currie, Lavery (Gielty 81), Dalziel (Ronald 90), O'Brien (Morris 82).
Subs Not Used: Bald, Fairburn, Miller.
Booked: Stephen Tulloch, Lavery, O'Brien, Dunlop, Dalziel.
Goals: Dalziel 3, O'Brien 14, Dalziel 34, Lavery 59.
Annan Athletic: Arthur, Black (Davidson 61), Weatherson, Watson, Bradley (Moffat 83), Chisholm, McNiff, Flynn, Love (Brannan 74), Mackay, Hopkirk.
Subs Not Used: McCrudden, Swinglehurst, Mitchell, Anderson.
Booked: Love, Watson.
Goals: Hopkirk 23, Love 38 pen.
Ref: Nick Walsh