Durham claimed the extra half hour in a bid to force a three-day win at home to Sussex, but after taking the ninth wicket in the first of the eight overs they were denied by James Tredwell and Lewis Hatchett.
More impressive bowling by Ben Stokes helped Durham to close in on their second successive championship win before John Hastings hastened Sussex's capitulation by grabbing four wickets.
Bad light brought an early tea, at which point Durham declared to set Sussex a target of 491. But what became a 46-over evening session was played in bright conditions and Sussex moved easily enough to 30 before Stokes knocked over the top three to complete his first 10-wicket match haul.
After Durham resumed on 105 for one, Keaton Jennings made 103 and Scott Borthwick 95 as they extended their stand to 200.
They added 116 before a brief shower arrived eight minutes before lunch with Borthwick the dominant partner after spending an hour over his first four runs the previous evening.
Having resumed on 46, Jennings coped comfortably with Jon Lewis's in-swing and drove a wide half volley through extra cover to reach 50 off 117 balls.
But when the bowlers started to concentrate on moving the ball away from him he failed to connect with several drives and was lucky not to get an edge.
Borthwick drove Lewis Hatchett wide of mid-on to complete his 50 off 121 balls and later hit Steffan Piolet for three fours in an over. He finally edged a good ball from the deserving Magoffin to second slip.
Jennings also edged to Tredwell when he attempted to cut Hatchett four balls after completing his hundred off 215 balls by clipping the same bowler behind square for his 13th four.
After catching the top three, Tredwell took the next two wickets.
Stokes smashed 31 off 25 balls before he tried to pull a ball which kept low and bottom-edged into his stumps. Then Paul Collingwood edged to slip before Michael Richardson and Gordon Muchall put on 58 in 12 overs prior to the declaration.
Chris Nash and Luke Wells began Sussex's second innings comfortably, but in Stokes' second over Wells edged low to Phil Mustard, who deflected the ball to Borthwick at second slip. For the unfortunate Wells it was identical to his first innings dismissal.
Nash edged a brutal lifter to Mustard, who clung on at head height, then in his next over Stokes had Rory Hamilton-Brown lbw and after five overs he had figures of three for 10.
He kept going for a further seven overs and returned for two more at the end but there was no more reward.
Hastings had Ben Brown caught by Borthwick before Piolet fell lbw, Luke Wright pulled a catch straight to deep square leg and Magoffin edged an airy drive to Mustard.
In the first of the additional eight overs Jon Lewis edged Chris Rushworth behind, but Tredwell reached 41 at the close with Hatchett on four.