England paceman Graham Onions and Chris Rushworth shared nine wickets to give title-chasing Durham maximum bowling points before Tony Palladino struck twice to leave the LV= County Championship match against Derbyshire at Derby in the balance.
Rushworth took 5-47 and Onions 4-62 to bowl the home side out for 298, which was built around 75 from Paul Borrington and 53 by Shivnarine Chanderpaul - plus 50 extras.
Derbyshire lost their last eight wickets for 92 but Palladino removed Durham openers Mark Stoneman and Keaton Jennings as the Division One leaders ended day two 216 behind on 82 for two.
Durham claimed the big wicket of Wayne Madsen with the fourth ball of the morning, but that was their last success for 41 overs as Borrington and Chanderpaul dug in to take Derbyshire past 200.
It looked ominous for Derbyshire when Madsen was caught on the crease and pinned lbw by Onions for 32 but the third-wicket pair slowly closed the door until the second new ball forced it back open.
Borrington was content to push the ball into gaps, although he reached his first championship half-century since the start of last season by pulling Usman Arshad for his sixth four. With Chanderpaul in a typically watchful mood, Durham's attack was blunted.
Paul Collingwood turned to his own medium pace to try and break the stand and he should have removed Chanderpaul on 22 when the West Indian edged to second slip where Scott Borthwick grassed a knee-high chance.
Durham must have feared the worst when Chanderpaul drove the erratic Jamie Harrison past point for his fifth four to reach his fifty off 119 balls, but he then played a walking drive at Arshad and was caught low down by Collingwood at first slip.
Richard Johnson pulled Arshad for six but the second new ball sparked a collapse that saw four wickets fall for six runs in 24 deliveries.
Borrington's 324-minute vigil was ended when Onions found late movement to have him caught at second slip and Johnson went the same way when he edged a firm push at Rushworth.
When Tom Poynton was caught behind without scoring and Alex Hughes chipped Onions to square-leg, Derbyshire were 248 for seven. Yet David Wainwright and Palladino added a precious 42 in 14 overs before Onions and Rushworth took the last three wickets for eight runs.
Stoneman looked in good touch as he hit six fours in his 30, but Palladino had him caught behind and then Jennings played on to leave the contest intriguingly poised.