Firbeck completed a Division One double over local rivals Clumber Park on Saturday to maintain their title chase and leave Clumber in midtable.
After heavy overnight rain, conditions were damp, and when Clumber won the toss they elected to bat.
Firbeck, however, made them pay and were outstanding in the field taking five catches and an impressive run out.
M. Dean (13) and D.Beard (24) started carefully and slowly and managed to nearly see off the opening bowlers.
But when Beard fell to N. Parry (2 for 24) and Dean to C. Tindle (1 for 31) it became a rout.
A. Dutton (2 for 8) and J. Hubball (4 for 5) ran through the lower order with the last eight batsmen adding only 26 to the score.
Clumber finished on a disappointing 79 all out, giving Firbeck a sniff of victory.
Clumber had other ideas however, and got the perfect start to their attack as Alistair Skinner (3 for 21) took two wickets with the first two balls of the innings.
But A. Dutton (39), J. Hubball (24) and A. Walker (10) saw Firbeck home in under 20 overs for the loss of just four wickets, and the 20 points were theirs.
In the Championship, Worksop had a losing draw with Caythorpe II.
The inform Bernhard Beukman did provide 57 runs however, Conor Smith stop scoring with 71.
Anston lost their derby game with Kiveton Park by five wickets.
Division One side Whitwell had a winning draw against Welbeck II, with Carl Curran unbeaten on 97 runs and Mark Forrest taking 3 for 38.