Essex 245 (Cook 84, Lawrence 61, Rhodes 5-17) and 316 for 9 (Cook 83, Lawrence 74, Rhodes 4-38) beat Warwickshire 161 (Siddle 5-33) and 213 (Banks 50, Harmer 6-75) by 187 runs

Simon Harmer claimed his seventh five-wicket haul of the season to help Essex to the top of the Specsavers County Championship with a 187-run victory over Warwickshire.

The South African offspinner took his season's tally to 64 with his latest figures of 6 for 75. He had done the damage in the morning session when he took four wickets in 20 balls to rip the heart out of an inexperienced Warwickshire batting line-up

Essex's seventh win in eight games - and sixth in six at Chelmsford - carried them above Somerset by four points with four to play, including a potential winner-takes-all showdown at Taunton in the final game.

Set 401 to win, Warwickshire were always in trouble. Essex were held up briefly by a lively seventh-wicket partnership between Michael Burgess and Henry Brookes that put on 51 in eight overs. But once Brookes went shortly before lunch, the die was cast. There was just enough time for Burgess to reach his first fifty since joining on loan from Sussex, before the end came 45 minutes into the afternoon session.

Shorn of chief run-getters Dom Sibley and Sam Hain on England Lions duty, Warwickshire did not possess the strength in depth to prevent a fifth defeat of the season.

It had taken six overs for the first wicket of the day to go; the rest kept falling at regular intervals thereafter. Rob Yates might have gone to the very first ball when he got a leading edge that went agonisingly just over Harmer's head. Not much eluded Harmer thereafter.

Liam Banks reached his maiden first-class fifty from his 81st ball faced, but six balls later he edged Peter Siddle firmly to Tom Westley at third slip. Yates hung around for 63 balls for 13 before he became Harmer's first victim, caught low down at slip by Sir Alastair Cook. Dan Mousley faced just one ball before he departed to the same combination.

Tim Ambrose survived the hat-trick ball, killing any turn with an exaggerated forward defensive stride, but lasted just two more overs from Harmer before popping one around the corner to Dan Lawrence at leg slip.

Adam Hose looked to be batting himself back into form with 13 from 34 balls when he played an injudicious sweep at Harmer and was caught at midwicket by Rishi Patel, diving forward.

Burgess and Brookes offered a measure of aggressive resistance. Burgess started the spree by lofting Harmer over cow corner. Brookes caught the prevailing mood by hooking Matt Quinn for four and six over midwicket and then landing a straight six off Harmer. Burgess's second six off Harmer took the stand past fifty in eight overs.

It was only delaying the inevitable, however. Brookes perished for 27 from 25 balls when he was strangled down leg side by Quinn and feathered to substitute wicketkeeper Will Buttleman, playing in place of the injured Adam Wheater.

The return of Siddle to the attack immediately after lunch accounted for Warwickshire captain Jeetan Patel, this time with Harmer assisting with the catch at second slip.

Burgess reached his half-century from 46 balls, but lost Olly Stone, the ninth wicket, with the score half the deficit, caught behind. Burgess was the last to depart, dancing down the wicket to Harmer and being stumped for 64. His innings had spanned 69 balls and included seven fours and three sixes.