Warwickshire's seam attack put the squeeze on Surrey as the LV= County Championship Division One leaders enforced the follow-on on day three at Edgbaston.
Rikki Clarke led the way with four for 46 while Chris Woakes and Keith Barker shared five scalps with Surrey dismissed for 286, having resumed the day on 109 for one.
Rory Burns top-scored with 77 at the top of the order and although there was some lower order resistance from Stuart Meaker (41) and Jon Lewis (33 not out), Sussex have it all to do if they are to avoid defeat.
After being asked to bat again, still 285 runs adrift of Warwickshire, Burns and fellow opener Zafar Ansari negotiated the final 18 overs of the day to close on 38 without loss and give the visitors some hope.
Victory in Birmingham could give Warwickshire some vital breathing room with title rivals Nottinghamshire's bowlers struggling to make any sort of breakthrough against Sussex at Trent Bridge.
Chris Read's men, just one point behind Warwickshire before the latest round of fixtures, looked to be cruising when James Taylor's unbeaten 163 helped them declare on 520 for four - a first-innings lead of 349.
But Sussex's openers put on an unbroken stand of 146, with Ed Joyce making an unbeaten 63 and Chris Nash on 79 not out - on a day where 26 overs were lost to rain to frustrate Nottinghamshire heading into the final day.
At the other end of the table, rock-bottom Durham sealed their first victory of the season by 15 runs over Middlesex in a low-scoring thriller at Chester-le-Street.
Chasing a target of 118, Middlesex resumed on 58 for five and their hopes of triumphing were boosted by nightwatchman Toby Roland-Jones steadily accumulating.
His dismissal for 34 after being caught behind off Graham Onions sparked a collapse as Middlesex lost their last three wickets for four runs in the space of 28 balls.