Essex 530 for 7 dec and 254 for 7 (Cox 116*) lead Kent 413 (Compton 165, Bell-Drummond 135, Critchley 5-105) by 374 runs

Cox, 23, reached his first three-figure score for his new county with a mighty six over square leg, one of six sixes in an unbeaten 116 as Essex raced to 257 for 4 and a lead of 374 in 40 over in a lengthy evening session. The fast accumulation of runs was necessary with rain and high winds forecast for the final day.

Wickets had been scarce on day two, but things were soon back to normal. Daniel Bell-Drummond had added just a single to his overnight score when he was late on a straight one from Jamie Porter. He had been in the middle for 73 overs with Compton while putting on 224 for the second wicket.

It was the breakthrough Essex needed after waiting so long. They had taken the new ball at the start of the day and it quickly accounted for Jack Leaning in Porter's next over, lbw to one that jagged in, before Shane Snater removed Joe Denly's leg stump to claim his 100th first-class wicket.

It was then over to Critchley, who flipped from end to end, taking wickets at both. Harry Finch misdrove to a stooping mid-off to the first ball of a brief spell from the river end, Jaydn Denly lunged extravagantly to loop a ball from the opposite end into short leg's hands and Wes Agar toppled forward to fall lbw as Critchley reverted to his original starting point.

However, that only brought in Nathan Gilchrist who pulled Critchley and Simon Harmer for sixes as he contributed 33 towards the first fifty of a 88-run stand with the immovable Compton.

Gilchrist was finally out for a career-high of 41 from 64 balls, having helped Kent avoid the follow-on, before edging Critchley behind where Michael Pepper grabbed the catch at the second attempt. Critchley's fourth career five-wicket haul was confirmed when Matt Parkinson thick-edged to slip.

Compton, 100 not out at start of play, watched the wickets tumble from the other end. He played one of the shots of the day when he rocked back and drove Harmer through the covers for four. But he was denied the honour of carrying his bat, bowled around his legs attempting to sweep Harmer.

When Essex batted for a second time, Dean Elgar survived a chance to Agar's third ball, dropped at the third attempt by a diving Finch. Elgar made Kent pay with 34 from 48 balls before Garrett trapped him lbw.

Kent had broken through when Feroze Khushi watched in horror as an injudicious pull off Agar ended up in deep midwicket's hands. Agar had a second wicket when Tom Westley played all around one and was lbw.

Cox quickly found his range, twice reverse-sweeping Parkinson for boundaries and then slamming two fours through midwicket and a six over extra cover in a Parkinson over that cost 19. That wasn't the end of the T20-style innings as sixes rained around Chelmsford. The ubiquitous Critchley hit 25 from 23 balls in a quickfire 87-run partnership with Cox before being bowled by Parkinson while Pepper helped add 91 for the unbroken fifth wicket.