Tim Groenewald and Tony Palladino bowled Derbyshire into a healthy position as 15 wickets tumbled on the opening day of the County Championship match with Somerset at Taunton.
The hosts were bowled out for a paltry 103 after winning the toss, Groenewald taking 5-33 and Palladino 4-34. Piyush Chawla top scored with 27.
Chawla then did his best to bowl Somerset back into the game, taking four for 87 but Derbyshire closed an incident-packed day on 220-5 and led by 117, with Tom Poynton (53no) and Richard Johnson (55no) having added 93.
Marcus Trescothick elected to take first use of a green looking pitch and saw his side nosedive into trouble from the moment he edged into the slips off Mark Footitt and departed for 17 with the total on 25.
Groenewald and Palladino then ran through the home side with some accurate seam bowling, aided by some poor shots in a game which could have a major bearing on the First Division relegation issue.
Nick Compton, James Hildreth and Craig Kieswetter managed just 20 runs between them and the younger batsmen in the middle order found the situation too much for them.
Somerset plunged to 75-9 and it took a counter-attacking innings from Chawla at the end to see them to three figures.
Derbyshire looked alert in the field and were soon putting conditions into perspective as openers Paul Borrington and Ben Slater built a half-century opening stand.
Somerset's seamers lacked the consistency of their opponents and it wasn't until Trescothick introduced Chawla for the 16th over that a breakthrough was made.
The Indian spinner had Borrington (27) picked up at slip with his first delivery and then produced a lifting leg-break to send back Wayne Madsen in similar fashion.
Craig Meschede belatedly struck a blow for the faster bowlers by pinning Shivnarine Chanderpaul lbw for four. But Slater (45) helped take the score to 121 before being caught at backward short leg off Chawla, having hit five fours.
Somerset looked to be back in it when Chawla picked up his fourth wicket, Alex Hughes falling leg-before for six pushing forward.
But Johnson responded positively and lifted Chawla for a straight six as he and Poynton rammed home Derbyshire's advantage with the most fluent batting of the day.
Poynton hit 10 fours in reaching fifty off 71 balls, while Johnson's half-century occupied 105 deliveries. By the close they looked in total command, as did Derbyshire.