Luke Wells revived Sussex's County Championship title challenge with a patient 110 on the first day of their Division One clash against Derbyshire at Hove.
The 22-year-old opener batted for a shade over six hours as Sussex were bowled out for 314 in the final over of the opening day.
Sussex were struggling on 144-5 at one stage after championship debutant Alex Hughes knocked back Rory Hamilton-Brown's off stump and then held a stinging return catch to remove Luke Wright for a second-ball duck.
But Ben Brown helped Wells add 45 before the latter put on 53 for the seventh wicket with Chris Jordan.
A green-tinged pitch offering good carry and occasional steepling bounce gave the Derbyshire attack encouragement all day, although too many Sussex batsmen were guilty of getting themselves established and then playing poor shots.
Wells and fellow opener Chris Nash survived for 17 overs until Nash slashed to third slip where Peter Burgoyne parried the ball and Shiv Chanderpaul, diving to his left at first slip, took the catch to give seamer Matt Higginbotham a wicket on his championship debut.
Four of the Derbyshire side boast just nine championship appearances between them and it was a memorable day for Hughes, a 21-year-old all-rounder who struck with his fifth ball when Mike Yardy sliced a drive straight to Ben Slater at backward point.
Sussex lost their third wicket when skipper Ed Joyce was caught behind to reward the persevering Mark Footitt, but Wells played with increasing assurance after a period of quiet accumulation before lunch when he scored only 27 runs, including successive boundaries off Tim Groenewald.
The left-hander got to his 50 from 138 balls with an on drive off Footitt and needed exactly 100 more deliveries to reach his second century of the season, a pull off Higginbotham for his 16th boundary.
He had moved onto 110 when Derbyshire skipper Wayne Madsen had him taken at mid-off off a top-edged pull.
Madsen had earlier taken his first championship wicket since 2010 when Brown clipped his first ball to midwicket but the visitors' attack lost their way in the final hour.
Jordan and Steve Magoffin took the total past 300 in a stand of 59 in 14 overs which was ended when the latter was caught behind off Groenewald, who then picked up Jordan (48) off a mis-timed drive to cover before taking the last wicket when Lewis Hatchett was trapped in front for a duck.