Derbyshire 306v (du Plooy 82, Came 78, Dal 56, Rushworth 3-60) and 214 for 9 dec (Madsen 58, Raine 5-43, Trevaskis 3-81) drew with Durham 223 (Jones 87, Conners 4-55) and 176 for 5 (Trevaskis 42*)
The sixth-wicket pair batted through the final 17 overs to steer Durham to a fighting draw after they had been set 298 in 87 overs. Trevaskis faced 57 balls for an unbeaten 42 and Coughlin was 19 not out off 53 as Durham closed on 176 for 5 from 53 overs.
Mark Watt took 2 for 37 in 13 overs but Derbyshire could not force the win that would have taken them to second in Division Two.
Durham paceman Ben Raine claimed two more wickets to finish with 5 for 43 in 22 overs before Derbyshire declared on 214 for 9. Derbyshire had batted on for seven overs, adding 29 runs for the loss of Anuj Dal and Nick Potts before the declaration came.
With showers forecast in the afternoon, they needed to make early inroads but Michael Jones again started positively, taking three fours from the second over from Nick Potts. Jones had scored 24 out of 26 when he tried to leave a ball from Ben Aitchison and got a bottom edge into his stumps.
Aitchison should have had a second when Sean Dickson on 11 edged him low to first slip where Watt spilled the chance at the second attempt. But Derbyshire had a second breakthrough in the next over when Scott Borthwick played across a low dipping full toss from Conners and lost his middle stump.
At lunch, Durham required a further 237 in 67 overs but their hopes took another blow when Dal removed Dickson. The allrounder thought he had the opener caught behind earlier and when Dickson missed a big swing and lost his off stump, he gave him a loud and visible send-off.
Durham's chances now rested with Nic Maddinson who drove Watt for consecutive fours before rain stopped play for 20 minutes with the loss of five overs.
When play resumed under threatening clouds, Watt broke through in the first over when Maddinson pushed forward at a ball that went on with the arm and was caught behind. Watt struck again in his next over, tempting Jonathan Bushnell into a drive which he edged low to Wayne Madsen at slip.
It was now a question of whether the rain would stay away but as the players were leaving the field for bad light, a storm broke over the ground, holding up play for two hours.
The umpires decided the match could resume at 4.50pm, which gave Derbyshire 17.1 overs or 103 balls to take five wickets. And there was drama immediately with Coughlin put down at second slip on 1 as he pushed forward at Watt.
Trevaskis and Coughlin showed application and good judgement to frustrate Derbyshire who, with seven overs left and the light deteriorating, were unable to use their pace bowlers. With spinners on at both ends, Derbyshire had every fielder in a catching position but the pair stood firm and the home side called off the hunt with one over remaining.
There was a touching finale as the players and coaching staff applauded umpire Nick Cook off the field in his last appearance at Derby before he retires at the end of the season.