Defending champions Sussex will need to bat for much of the final day at Hove after closing day three a distant 212 runs behind Nottinghamshire at 7-0.
Mark Wagh ended a run of 13 months without a first-class century as Notts amassed 558-7, a lead of 219.
He shared 173 in 53 overs with Matthew Wood as Sussex, still reeling from the retirement of spinner Mushtaq Ahmed, went wicketless between lunch and tea.
Sussex survived six overs before the close but have much still to do.
The home attack was noticeably lacking potency, and claimed only five wickets in dull conditions at Eaton Road.
South African left-hander Ashwell Prince was the one wicket to fall before lunch, caught off the glove at slip in the 13th over of the day.
Wagh, who had fallen three times in the 90s since hitting 152 against Northants last July, reached three figures in style with an on-drive off Robin Martin-Jenkins.
He was finally caught at mid-off, while Wood, whose previous highest this season was 77, was out shortly afterwards lbw playing across the line.
Spinner Ollie Rayner dismissed Paul Franks and veteran Mark Ealham in the space of three balls, but eighth-wicket pair Chris Read and Rob Ferley took Notts more than 200 ahead by adding a fluent 42 before the declaration.
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