Luke Wells scored his third consecutive century against Surrey to put Sussex in a good position at the end of the second day at The Oval.
Chris Jordan took the final three Surrey wickets to bowl the hosts out for 351 after they resumed on 301-7 to finish with figures of 5-92.
Wells then took centre stage as he finished unbeaten on 108 from 253 balls and his partnership of 104 with skipper Ed Joyce guided Sussex to 204-2 at the close – still trailing by 147 runs.
It was the 22-year-old’s sixth first class century and his third in four games against Surrey who must be sick of the sight of him.
Wells had survived two big appeals – one off the bowling of Gareth Batty the other off Chris Tremlett - when he had made just 11 but Chris Nash was not so lucky.
The Sussex opener was disgusted to be given out lbw to Tim Linley for 12 just before lunch and raised his bat to the umpire to suggest he had got an edge on to his pads.
Runs were proving difficult to come by on a slow pitch and Michael Yardy has taken 96 balls for his 23 before being caught at leg slip off the bowling of Batty just before tea. Once again the batsman showed displeasure at the decision, feeling it was a bump ball.
That brought Joyce and Wells together with the score on 100-2 and the two left handers batted through the entire evening session without much incident.
Linley did have one big lbw shout against Joyce when he was on 14 but otherwise there were few scares – although the biggest test will come in the morning when Surrey have use of the new ball.
Wells brought up his hundred by hitting Vikram Solanki to the ropes in successive balls while Joyce reached his half century in the final over before the close.
Earlier, Surrey had picked up a fourth batting point thanks largely to the efforts of Gareth Batty and Chris Tremlett Surrey resumed on 301-7 but Batty and Tremlett took their partnership to 61 before the introduction of Jordan brought instant success for Sussex. Batty hooked Jordan’s first ball straight to Wells on the square leg boundary to depart for 37.
Jordan then bowled Tim Linley through the gate for three and produced a brilliant yorker to remove Tremlett for 34 after the England bowler had hooked him for six the previous ball.
That gave the former Surrey seamer figures of 5-92 and means he has taken 13 wickets in three innings at an average of 14 since joining Sussex in the winter.
James Anyon finished with figures of 3-86 and Steve Magoffin 2-74 meaning all ten wickets fell to former Surrey players.