A moment of controversy soured the final afternoon at Wantage Road with Billy Godleman standing his ground after a fair catch was claimed by Jake Libby.
It mattered not in the wider context of the game with Derbyshire taking tea 180 for 0, 34 runs ahead at Wantage Road.
Godleman drove to Libby at deep point who took the catch down low. But Godleman refused to move and a long conversation began with umpires Martin Saggers and Russell Evans.
Despite both umpires being at least 70 yards from the fielder, they decided Godleman was not out.
A long protest from Northants captain Alex Wakely followed but Godleman was allowed to bat on and reached tea 66 not out.
There was nothing to taint the innings of Chesney Hughes who went into the 90s for the third time this season, 94 not out at the second break.
The only danger came from the spin of Graeme White but Hughes and Godleman used their feet smarty against the left-arm spinner and both lifted him for six over midwicket.