Murray Goodwin ended his run drought to give Sussex hope of salvaging a draw against Nottinghamshire at Hove.
Goodwin ended the third day unbeaten on 52 after sharing in a fifth wicket partnership of 78 with Luke Wright.
Wright was also still there at the close on 37 as Sussex reached 177-4 going into the final day.
That gives them a lead of 58 after they bowled out Nottinghamshire, who resumed on 320-4, for 428 in the morning.
Riki Wessels fell one run short of his double century when he was caught behind off Steve Magoffin while James Anyon picked up the wickets of Adam Voges, Ben Phillips and Andre Adams to finish with figures of 3-132.
Chris Read made 45 to stretch Nottinghamshire's lead past 100 before becoming a third wicket for Chris Nash, who had figures of 3-23.
Nash and Ed Joyce got Sussex's second innings off to a solid start with an opening stand of 64.
Nash was trapped lbw by Andy Carter to spark a collapse as three wickets fell for the addition of only four runs.
Joyce was bowled by Samit Patel for 31 and Joe Gatting had his off stump knocked back by Carter.
Skipper Mike Yardy became Carter's third victim in the second over after tea to leave Sussex in trouble on 99-4 but Goodwin and Wright steadied the ship.
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