Three heavy showers ensured that only 17.2 overs could be bowled in the morning session but in that time, Lancashire took the new ball and James Anderson bowled Martin Andersson for 54 with a superb delivery that was angled into the batter but straightened and knocked out the off stump.
That ended Andersson’s 110-run fourth-wicket stand with Guest, which was the innings’ third successive partnership above 56, and four overs into the afternoon session, Mitch Stanley took his third wicket when he trapped Guest lbw for 83.
Tom Bailey replaced Anderson and with the 12th ball of his spell, he took a sharp return catch off a checked drive to dismiss Anuj Dal for 21, a 23-ball frivolity that had included five fours.
That left Derbyshire on 319-6 and half a dozen overs later, Coughlin took his first wicket for his new county when he had Chappell leg before wicket for 11. Having had two chances dropped on the second day, Coughlin had clearly decided to cut out the middle man.
In his next over, the former Durham bowler took his second wicket when Ben Aitchison’s swish merely nicked a catch to Hurst and 20 minutes later, Coughlin had completed his memorable spell of 4.3-1-15-4, removing Luis Reece (36) and last man Abbas for eight.
However, the merits of Lancashire’s seamers were quickly forgotten when the 47-over evening session began. Luke Wells had his off stump knocked back by the sixth ball of Abbas’s first over and 10 minutes later Josh Bohannon was caught by second slip Caleb Jewell off Abbas for four.
Harris and Harry Singh resisted for half an hour but any calmness or solidity was deceptive.
Having made 10, Singh drove a return catch to Chappell, who completed the dismissal at his fourth attempt. Michael Jones clipped his second ball off his toes to midwicket where Shoaib Bashir took a good low catch and Chappell then took his third wicket in 10 minutes when Matty Hurst’s loose drive diverted the ball via bat and boot onto the stumps.
Tom Hartley joined Harris and the pair mounted a partial recovery, putting on 55 in 65 minutes before Hartley was bowled by Anuj Dal for 24.
Coughlin and Harris then put on an unbroken 69 and there is every chance Derbyshire will face a testing target of around 170 on the final day.
Report by ECB Reporters’ Network, supported by Rothesay.