Simon Harmer spun Essex to the brink of the Specsavers County Championship title with seven wickets as reigning champions Surrey were despatched by an innings at Chelmsford.
With Somerset beaten earlier in the day, Harmer helped Essex reclaim top spot by 12 points with one game to play. They head to Taunton next week knowing they need to avoid defeat to guarantee another title.
Captain Ryan Ten Doeschate completed his hundred in the morning session before a rapid fifty by Harmer saw Essex all out for 395.
Surrey needed 221 runs to make the hosts bat again, but they could only manage 181 despite some resistance from Jordan Clark and Morne Morkel, who both stuck around for 80 balls, until Harmer bowled his fellow South African to finish with seven for 58.
In Southampton, Kyle Abbott claimed Hampshire's best-ever bowling match figures and the fourth-best in the County Championship history as Somerset's hopes of winning the title took a hefty blow at the Ageas Bowl.
The South African had taken nine for 40 in the first innings and replicated his incredible fast bowling with a remarkable eight for 46 to blow Somerset away again with match figures of 17 for 86 – the Championship's first 17-wicket haul for 80 years.
Hampshire were 176 for eight overnight and captain James Vince added another 40 to his score before he was out for 142 as Somerset were set 281 for victory.
Sam Billings became the first player to score two hundreds in the same County Championship match at Emerald Headingley as Kent set Yorkshire a target of 551 shortly after tea on day three and hurtled towards victory with six wickets.
Kent's captain struck 122 not out with Ollie Robinson falling three short of a century before they declared on 337 for seven.
Any hopes Yorkshire had of making it to the close unscathed were hurt by Darren Stevens, who claimed four for 12, to leave them on 44 for six.
Dominic Sibley's 215 not out has put Warwickshire in a strong position going into the final day at already relegated Nottinghamshire.
The England hopeful helped his team reach 498 all out before they had the hosts in trouble on 105 for five – a lead of 115 – with Joe Clarke unbeaten on 59.
In Division Two, Northamptonshire are on the cusp of promotion and need two more wickets to defeat visiting Durham.
Luke Procter's 86 not out helped the hosts set 402 for victory and the away side closed day three on 212 for eight with Brett Hutton taking four for 54.
Gloucestershire completed a six-wicket victory at Worcestershire, reaching their target of 115 to remain in the mix to finish second.
Derbyshire secured a 181-run win at home to Sussex after setting the visitors 345 to win, having been dismissed for 437.
Lancashire, despite Keaton Jennings' second-innings 97, lead Middlesex by 211 runs at Old Trafford, but with only two wickets in hand Dawid Malan's team will fancy their chances of a final-day victory.
At Cardiff, Leicestershire require 424 to beat Glamorgan, but closed on 32 for two after Kraigg Brathwaite hit an unbeaten 103 to help the hosts declare on 251 for five in their second innings.