Centuries from Simon Harmer and Tom Westley put Essex in complete command against Surrey at the Kia Oval, where the champions ended day two facing their first defeat of a triumphant season.

At stumps, Surrey were 88 for one in their second innings – still 322 runs behind – after Harmer, Westley and Adam Wheater, with a punchy 68 from 105 balls, had swept Essex to 441 for eight declared.

Mark Stoneman, dropped on five off Matt Quinn by replacement keeper Michael Pepper – who dived across first slip but only succeeded in deflecting the edge into Murali Vijay’s left knee – moved confidently to 41 not out from 63 balls, although Rory Burns gave Jamie Porter a simple return catch on 21 when Surrey’s captain attempted to flip a short ball to leg but got a leading edge instead.

Harmer and Wheater added an unbroken 159 in 36 overs in the afternoon session, establishing a new seventh wicket record for Essex against Surrey, and piling on the agony for the runaway Specsavers County Championship winners after Westley’s dismissal in the last over before lunch.

Wheater, however, had to retire hurt during the tea interval after failing to shake off a nasty blow to his right thumb, suffered four balls before the interval when former South Africa fast bowler Morne Morkel made one rear from a good length.

Harmer then saw Porter and Sam Cook both fall to the persevering Jade Dernbach, who finished with a creditable four for 95, before swiping off spinner Amar Virdi for six over the head of the long-on fielder to reach only his second first-class century.

The declaration came soon afterwards, with Harmer unbeaten on 102 from 156 balls, with 11 fours and two sixes – both off the suffering Virdi.

Essex, the 2017 champions, were already in charge when starting day two 130 runs in front.