Surrey 67 and 88 for 1 (Stoneman 41*) trail Essex 477 for 8 dec (Westley 134, Harmer 102*, Wheater 68*) by 322 runs
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 1 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 8 declared.
Mark Stoneman, dropped on 5 off Matt Quinn by replacement keeper Michael Pepper - who dived across first slip but only succeeded in deflecting the edge into M 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 on a pitch that otherwise played much better than on the opening day.
Harmer then saw Porter and Sam Cook both fall to the persevering Jade Dernbach, who finished with a creditable 4 for 95, before swiping off spinner Amar Virdi for six just 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 of the match when starting day two 130 runs in front at 197 for 2, but they continued to build a position of utter dominance after Westley quickly completed the 20th first-class hundred of his career.
Resuming on 93, Westley took just 12 balls to go to three figures and went on to 134 before tickling a leg-side ball from Rikki Clarke to keeper Ben Foakes to leave Essex 282 for 6. But the afternoon session belonged to Wheater and Harmer as they crushed any realistic hopes of an unlikely Surrey fightback.
Essex, who bowled out Surrey for a mere 67 in early bowler-friendly conditions, lost both Dan Lawrence and Ravi Bopara in the second day's opening hour. Lawrence was leg-before to Clarke having battled through 77 balls to make 17, and Bopara had scored just 8 when he attempted a paddle-sweep against Virdi - in the last over before the second new ball was taken at 238 for 4 - and was bowled behind his pads.
But Westley stood firm, joined in a fifth-wicket stand of 40 by Ryan ten Doeschate before the Essex captain edged Dernbach to gully to go for 27. When he was finally dismissed, Westley had batted for almost six and a half hours, facing 282 balls and hitting 21 fours.
Wheater hit eight fours and a six over long-on off Virdi, but was replaced as keeper by substitute Pepper when Surrey batted again. And Essex needed another replacement when seamer Cook could not pass a concussion test - following a blow on his batting helmet during his brief innings, facing Dernbach - and so called up Matt Coles to deputise.