Skipper Ed Joyce underpinned Sussex’s batting again – and frustrated Championship leaders Yorkshire in front of a big crowd.
Joyce fell to final ball of day one at Scarborough after reaching 130 from 240 deliveries, including 15 fours.
Sussex kept most a crowd of 4,624 a little concerned as they reached 315-8 by the close and Yorkshire still have a lot of work to do if they are to extend their five-point lead at the top of the table.
On a bright morning with a brisk but cool wind, Yorkshire chased leather as Chris Nash and Luke Wells got Sussex off to a rapid start, with Nash the more dominant of the two.
He slammed Ryan Sidebottom's third ball to the cover boundary and pulled consecutive fours off Jack Brooks, 30 runs coming from the first five overs before Tim Bresnan took over from Brooks.
It was Sidebottom, however, who hit back by taking two wickets in four balls to stem the tide, Nash edging a fast catch to Adam Lyth at second slip and Wells playing defensively only for the ball to bounce back on to his stumps.
Joyce, though, always looked comfortable against an attack of inconsistent quality and Craig Cachopa overcame a hesitant start to raise the 50 stand with a boundary off Adil Rashid just before lunch to make it 99-2.
The Sussex captain continued to trouble Yorkshire in the early afternoon, advancing his score with some fluent cover drives to reach 50 from 120 balls with six fours.
But he enjoyed an escape on reaching 60, slicing Bresnan to third slip where Kane Williamson dived to his left and got his finger tips to the ball but could only divert its path to the boundary.
Cachopa cover drove Brooks for his seventh four to complete his half-century off 127 deliveries but three runs later he gave catching practice to the slip cordon and Lyth made no mistake to end their third wicket partnership of 124 in 44 overs.
Sussex were still well placed at 169-3 and Luke Wright was the livelier either side of tea in a 68 stand with Joyce, galloping to his 50 from 73 balls with seven fours.
After Wright departed, Joyce advanced towards an unflustered century, his fifth of the season, before he was trapped by Rashid.