Ed Joyce's unbeaten 129 took Sussex to 363-4 at stumps on the second day of their LV= County Championship match against Nottinghamshire at Trent Bridge.
The 30th first-class century of the left-hander's career - and fifth against Nottinghamshire - came from 138 deliveries faced, with 15 boundaries.
Sussex captain Joyce made an immediate impact after arriving at the crease in just the fifth over of another rain-reduced day.
With play not beginning until mid-afternoon Joyce's innings gained some early impetus as his first seven scoring shots all found the boundary boards.
The 34-year-old found a capable ally in Rory Hamilton-Brown who equalled his best score of the season with an undefeated 77, made out of an unbroken fifth-wicket partnership of 158.
Hamilton-Brown, who arrived at the crease possessing a meagre average of around 28 for the season, belied those figures with a controlled and well-grafted half-century, which arrived from 72 balls, with nine fours and one towering six off Samit Patel.
Sussex had earlier lost Chris Nash, for 46, in the fifth over of the day as Patel took a sharp low catch at second slip, from the bowling of Luke Fletcher.
Nottinghamshire broke through again when Ajmal Shahzad replaced Fletcher in the attack and saw Michael Yardy pull his first delivery straight into the waiting hands of Harry Gurney at fine leg.
Yardy, with 35, had offered valuable support to Joyce and Matt Prior then maintained the pressure with a punchy innings of 30, out of a fourth-wicket stand of 45.
Prior, just a couple of weeks ahead of the opening Ashes Test at Trent Bridge, got off the mark with a four off Shahzad and continued to play in an attacking vein until missing a pull off Fletcher to fall lbw on the stroke of tea.
The final session totally belonged to the visitors, though, as the Nottinghamshire bowlers toiled under slate grey skies as Sussex successfully collected four batting bonus points.
Hamilton-Brown passed 50 for only the second time this summer and moved within sight of his first century since returning for a second stint with the Hove club during the winter.