Essex 197 for 2 (Westley 93*, Vijay 80) lead Surrey 67 (Porter 4-26, Cook 4-27) by 130 runs
County champions Surrey were skittled for 67, their lowest Championship total at The Oval for 56 years, as Jamie Porter and Sam Cook bowled Essex into a position of first-day dominance with four wickets apiece.
By stumps, on a pitch that eased significantly in the second half of the day, the 2017 title-winners were already 130 runs in front with M Vijay and Tom Westley putting on 146 in 43 overs for the second wicket to take Essex to 197 for 2 in reply. India Test opener Vijay scored 80 from 127 balls, with 10 fours, before edging Jade Dernbach to the keeper while Westley remained 93 not out. The former England batsman has faced 201 balls, hitting 15 fours.
"It would have been nice to have got to my hundred tonight, but the most important thing is the team's position," Westley said. "Credit too to Murali Vijay for the way he played but our bowlers were outstanding this morning.
"It's tough for batting when you start at 10.30 on a September morning but Porter and Cook nip the ball around off the seam whereas Surrey's quicker bowlers are more swing bowlers, so perhaps that helped us a bit. It was still quite tough batting out there later today but the pitch has definitely got a bit easier too."
Vijay and Westley did both enjoy some moments of luck against Surrey's seam attack but they also played strokes of quality in a potentially match-defining stand after coming together when Morne Morkel bowled Nick Browne for 2 in the fifth over of Essex's first innings. It was Vijay's fourth score of 50 or more in four innings since joining Essex.
Earlier, Surrey had crumbled to 57 for 7 by lunch and their lower order managed just ten more runs in two overs after the interval as Porter and Cook finished the demolition job in some style.
Only Ollie Pope, last out for 26 from 53 balls, and opener Rory Burns, who made 19 before falling in the 16th over, provided any real resistance for Surrey as Porter, Cook and fellow seamer Matt Quinn ran amok on a well-grassed surface. But Pope needed some moments of good fortune, too, being dropped on 9 at square leg by a diving Ryan ten Doeschate when he mishit a pull at Porter and also escaping when he inside-edged a wicked delivery from the same bowler on 11 and saw keeper Adam Wheater fail to cling on as he dived away to his left.
Perhaps surprisingly, there was a toss - with Essex also presumably planning to bat first - but it soon became evident that first session conditions were very much in favour of the quicker bowlers, with both movement off the pitch and uneven bounce making life desperately difficult for batsmen.
Mark Stoneman edged Porter to Wheater behind the stumps in the fifth over, to go for 2, and the same bowler nipped one into Jason Roy's pads in his next over to send back the No. 3 for 5.
Surrey captain Burns, the Specsavers Championship's leading run-scorer who was called up to England's Test squad for the autumn tour of Sri Lanka last week after piling up more than 1300 runs in Division One at an average approaching 70, battled hard for 52 balls before being brilliantly held by Simon Harmer diving forward at second slip - right-handed and millimetres from the turf - off Quinn.
Ben Foakes was leg-before to Quinn's next ball, leaving Surrey 41 for 4, and although Will Jacks survived the hat-trick ball he was soon bowled for 0, driving loosely at an inswinger from Cook. And 21-year-old Cook then shaped one back into left-hander Ryan Patel's pads to dismiss him for 5.
A miserable opening session for Surrey was completed when Rikki Clarke departed for 0, beaten by another Porter offcutter in the seamer's second spell, this time from the Pavilion End. Porter, whose first spell of 7-0-19-2 set the tone for a dramatic morning, was well supported by both Quinn, whose single spell brought him figures of 6-2-10-2, and Cook. All three bowled with exemplary control of line and length.
Porter also removed Morkel for 1 in the first over after lunch, caught at the wicket, while Cook bowled Dernbach for 4 through a heave to leg and then had Pope caught at midwicket. It was Surrey's lowest first-class total since their 64 against Hampshire at Basingstoke in 1986 and their lowest at The Oval since 1962 when Warwickshire bowled them out for 61.