Hampshire finished the first day in the ascendancy after recovering from 208-6 to make 286 all out and then reduce Essex to 55-2 at stumps.
The visitors lost opener Tom Westley and Ravi Bopara in the first 14 deliveries of their innings and at stumps trailed the joint LV= County Championship Division Two leaders by 231 runs.
Essex will reflect on a day of missed opportunity, having put Hampshire into bat in overcast conditions and been in the box seat at the end of the second session. But Hampshire's last four wickets, aided by a significant 41 extras, added 78 runs, to post a competitive total.
Essex faced an hour's batting at the end of the final session and were quickly 2-2.
With his third delivery, South Africa Test paceman Kyle Abbott bowled Westley, offering no shot. One run and 11 balls later, Bopara gloved a catch to Michael Bates off the left-arm swing of James Tomlinson to leave Essex in trouble.
James Foster (26 not out) and Nick Browne (19 not out) successfully navigated the remainder of the session to see Essex through to the end without further loss.
Alexei Kervezee staged a one-man rescue act with his second century of the season as top-of-the-table Worcestershire slumped to 237 all out against Leicestershire at Grace Road.
It might not have been the most elegant of knocks by the 24-year-old Dutchman, but it was certainly a gritty and vital one on a bowler-friendly day.
Only four other batsmen reached double figures, and the next highest scorer after Kervezee was 19-year-old Tom Kohler-Cadmore with 32 - his Championship best. The teenager shared a fourth-wicket stand of 77 in 23 overs with Kervezee, who was ninth out for 102 off 142 balls with 16 fours.
At one stage it looked as though Worcestershire would fail to pick up a batting point when they were 167-7. But the last three wickets put on 70 runs in 10 overs. Charlie Shreck finished with 3-65 and there were two wickets apiece for Nathan Buck, Richard Jones, who is on loan from Warwickshire, and Ben Raine.
But the Leicestershire batsmen also struggled in the conditions. Both Angus Robson and Ned Eckersley were caught in the slips fencing at balls outside the off stump and when bad light brought an early end to the day's play Leicestershire had reached 58-2.
Glamorgan's bowlers made the most of helpful conditions as Kent's batsmen were restricted on the first day of their match at Sophia Gardens.
Despite winning the toss only captain Rob Key really dominated the home attack with 63, although Ben Harmison (33) and Adam Ball (42) held Glamorgan up for more than 20 overs after tea as the visitors closed on 236-8.
Michael Hogan claimed three wickets with Jim Allenby and Andrew Salter sharing two apiece.
Bad light struck with play being abandoned for the day with four overs remaining.
Tom Curran demonstrated his considerable promise with a career-best five-wicket haul that spearheaded an impressive Surrey bowling performance as Derbyshire collapsed to 153 all out at the 3aaa County Ground.
The 19-year-old South Africa-born seamer bowled with pace and control to take five for 51 from 17.4 overs in only his sixth first-class match while Jade Dernbach took three for three in eight balls as Derbyshire lost their last seven wickets for 53 runs in 77 balls.
Marcus North top-scored with 44 but it was a disappointing batting performance by Derbyshire and although Mark Footitt removed Rory Burns with the second ball of Surrey's reply, Hashim Amla played some cultured strokes as the visitors reached 44-1 when bad light forced an early close.