The Devils were well served by Berwick’s Kevin Doolan, who scored a 12-point maximum as a guest replacement for the unfit Kyle Newman.
It proved another sound all-round performance by Plymouth, who had double figure returns from Jack Holder, Sam Simota and acting skipper Todd Kurtz. Reserve Stefan Nielsen also weighed in with a couple of race wins.
Peterborough had sound contributions from reserve with Tom Perry and Simon Lambert scoring 15 points between them, but the Panthers lacked a cutting edge at the top end.
They did not produce a race winner until Ulrich Ostergaard won heat 11 and their only other first place came from Michael Palm Toft in heat 14.
Plymouth: Rider replacement for Charlie Gjedde, Kevin Doolan 12 (4 rides), Jack Holder 12 (6), Todd Kurtz 10+1 (5), Sam Simota 11+1 (6). Reserves: Stefan Nielsen 7 (5), Ellis Perks 0 (4).
Peterborough: Ulrich Ostergaard 9 (5), Emil Grondal 0 (3), Nikolaj Jakobsen 8 (4), Michael Palm Toft 8+1 (6), rider replacement for Nickolas Porsing. Reserves: Simon Lambert 6 (6), Tom Perry 9+5 (6).