The hosts pulled one back through Mark Nicholson but the scorer was later dismissed for violent conduct.
Paul Currie and David Greenhill were on target before Radzynski completed the rout with a left-footed drive.
Elgin: Gibson, Edwards, Niven, David W Craig, Tatters, MacAulay, MacDonald (Crooks 69), Nicolson, Sutherland (Cameron 76), Gunn (Calder 79), Frizzel. Subs Not Used: Steven Dunn, David A Craig.
Sent Off: Nicolson (57). Booked: MacDonald. Goal: Nicolson 26.
Berwick Rangers: Peat, Notman, Ewart, McLean, McMullan, McLaren (McGregor 83), Currie, Russell, Greenhill (Cropley 83), Radzynski, Little (Gray 76). Subs Not Used: McCaldon, Horn.
Booked: McLean, Russell. Goals: Little 14, Radzynski 24, Currie 65, Greenhill 70, Radzynski 82.
Att: 307
Ref: C Brown
Source: BBC Sport