The visitors enjoyed a successful second day of play in Chesterfield.
An astonishing day on which 24 wickets fell ended with Northamptonshire closing in on victory against Derbyshire at Chesterfield.
After Ben Sanderson took 5 for 46 to bowl Derbyshire out for 146 with Fynn Hudson-Prentice unbeaten on 55, Tony Palladino claimed 4 for 33 as Northants were shot out for 122.
That left Derbyshire chasing 319 for victory but by the close, they were 155 for 5, still 164 runs short of the target.
A pitch offering spin and variable bounce was certainly demanding to bat on but lack of foot movement and poor shot selection accounted for the majority of the wickets.
The carnage began when Wayne Madsen played across the line to give Sanderson his first victim and the rest of the day became a procession as wickets tumbled to a rash of poor strokes.
Tom Lace and Leus du Plooy paid the price for failing to get forward as Derbyshire slipped to 60 for 6 before Hudson-Prentice took 22 from a Rob Keogh over.
Matt Coles struck with his third delivery by trapping Matt Critchley on the crease but Hudson-Prentice reached 50 before Keogh wrapped up the innings giving Northants a lead of 196.
They chose not to enforce the follow-on but instead of an afternoon of accumulation, Northants moved into T20 mode and were bowled out in a chaotic session on a pitch which had clearly put doubts in the minds of the batsmen.
Ricardo Vasconcelos was run out attempting a second to deep square leg and after Luke Proctor offered no shot to Hudson-Prentice, Palladino profited from inadequate technique and ill-judged shots.
Keogh played across the line, Adam Rossington drove wildly at his first ball and although Temba Bavuma and Josh Cobb briefly threatened to restore order, more frantic shot selection sent the innings into terminal decline.
Cobb drove Critchley to long off and Bavuma fell victim to the mood of recklessness when he skied Palladino to point.
Hamidullah Qadri beat Coles’s charge and less than 31 overs had been bowled when Saif Zaib holed out to leave Derbyshire facing the highest successful run chase at Queen’s Park.
They clearly decided to approach it in a positive way as Billy Godleman and Luis Reece came out swinging in the late afternoon sunshine.
Godleman repeatedly charged the opening bowlers before he was stumped for 25 off Sanderson in the fifth over and Madsen lost his middle stump trying to work Coles through midwicket.
Reece was lbw playing back to Keogh and Luke Proctor struck twice in his first over to leave Northants favourites to wrap up victory tomorrow.