Derbyshire 153 for 6 (Hughes 50*) trail Northamptonshire 218 (Newton 67, McKerr 5-87) by 65 runs
Conor McKerr picked up a maiden five-wicket haul in just his second first-class match but his Derbyshire side ended the first day only even against Northamptonshire at Wantage Road.
McKerr, the 19-year-old on loan from Surrey, took 5 for 87 as Derbyshire bowled Northamptonshire out for just 218 before Northants produced a marginally better display with the ball and, through Ben Sanderson and Nathan Buck, reduced the visitors to 108 for 6 before Alex Hughes battled away with an unbeaten half-century to seer his side to the close on 153 for 6, trailing by 65.
Derbyshire had suffered a worrying early blow when Luis Reece left the field in the morning session complaining of breathlessness. He was taken to hospital and is being kept overnight at Kettering General.
Sanderson struck with the first ball of the Derbyshire reply, trapping makeshift opening Jeevan Mendis lbw. His second spell produced an edge from Gary Wilson that was taken at the second attempt by stand-in wicketkeeper Ben Duckett, and one that came back in to fix Daryn Smit lbw for 4, continuing the South African's poor form.
In between there were poor strokes from Billy Godleman driving loosely and presenting an edge to Alex Wakely at second slip off Rory Kleinvelt, and Shiv Thakor, who made a quick 45 including seven boundaries before flashing outside his off stump and getting a thin edge to Duckett.
Thakor's wicket was the first of the game for Buck, who followed up by winning an lbw verdict against Wayne Madsen, another South African out of touch. But a stand of 43 between Alex Hughes - who went past fifty in 83 balls with five fours - and Tom Taylor, who ate up 48 balls for his 7 not out, battled Derbyshire back into the game.
Northants had got themselves back on top, despite having little to play with after a batting effort lacking in discipline to occupy the crease on a green-tinged wicket but not one offering excessive seam movement.
Derbyshire arrived buoyed by a near-miss at Trent Bridge last week and, with McKerr to add an edge to their attack, hurried Northants away from 134 for 3 when Rob Newton and Duckett were going very well in a stand of 78 for the fourth wicket.
Newton played with fluency, driving confidently and pulling Hughes to the midwicket boundary. A well-timed off-side push brought him a fourth Championship fifty of the summer in 83 balls with seven fours. Only later in the day did his 67 realise its true value.
Duckett, returning from England Lions duty, also looked full of confidence and struck two perfect straight drives, then took further boundaries with flourishing strokes through extra-cover off Tony Palladino to reach 36.
But it was Palladino who found the breakthrough to begin the collapse. Duckett dragged a cover drive into his stumps and Newton followed three overs later to the same bowler, trying to punch off the back foot and edging to wicketkeeper Smit. Palladino also removed Buck who dabbed at a ball just outside off and got an edge into his stumps.
Before Buck's wicket, McKerr - who removed Wakely and Rob Keogh before lunch - returned to have Josh Cobb splendidly held in the gully by Alex Hughes for a six-ball duck, driving far too loosely outside his off stump, and picked up a fourth wicket with Sanderson held in the gully.
The most galling dismissal of the innings was that of Chesney Hughes, playing against his former county. Trying to pull a long hop from part-time offspinner Madsen, he got a miserable top-edge to extra-cover.
Kleinveldt lifted two sixes over point and a third over midwicket - all to the short boundary - as Northants limped to a first batting point. Kleinveldt was last man out miscuing a pull that was taken by Smit to hand McKerr a first five-wicket haul.