Two late wickets for Gareth Batty gave Surrey a glimmer of hope that they can force victory over Second Division promotion rivals Hampshire at The Oval.
Batty removed Jimmy Adams for 79 after the visitors' skipper had helped Will Smith put on 129 for their second wicket and then had James Vince trapped in front for seven as Hampshire finished the third day on 167-3 - 307 runs behind - after Surrey had declared 30 minutes before lunch on 474-8.
Earlier, Surrey's hopes of accelerating before their declaration were hit when Jason Roy, who had scored a run-a-ball 114 on the second day, was leg before playing back to Kyle Abbott off the first ball of the day.
A limping Jacques Rudolph cruelly missed a third consecutive Championship century in Glamorgan's battle to hold off Worcestershire in a gripping clash at New Road.
Facing the home side's total of 352 - after a career-best 85 by 19-year-old Tom Kohler-Cadmore - Rudolph became a victim of his incapacity when he was run out for 88 as the Welsh county closed day two on 222-6, still 130 behind.
Having batted without fault for four hours, mostly with Tom Lancefield acting as his runner, the South African played a ball from Joe Leach to mid-wicket and saw Lancefield beaten by Saeed Ajmal's direct throw to the bowler's end.
Jesse Ryder helped himself to a belligerent century while Ravi Bopara finished unbeaten on 98 as Essex completely dominated the second day of their clash with Gloucestershire at Chelmsford.
Ryder struck a magnificent 133, his first for the county, as he returned to form after his previous six championship games had brought him just 152 runs with a top score of 45.
Essex were 425-3 at the close - a lead of 201 runs.