Sussex seamer Henry Crocombe took his second hat-trick in eight days to help condemn Essex to 177 all out having been 171-3 just 26 balls before.
His sensational outing marked his third five-wicket haul in the County Championship this campaign, and just his second professional hat-trick after his first came against Somerset's tail in his side's last County Championship game.
Crocombe - who is set to sign for Surrey at the end of the season - finished the innings with an impressive 5-39, leaving his side with a first-innings lead of 102, which was extended to 188 by the end of play with Sussex 90-4 on day two.
Elsewhere, Surrey and Yorkshire traded blows with the ball in an incredible day two at the Oval that featured a staggering 23 wickets falling.
Jack White (3-14), Ben Coad (3-22), George Hill (2-17) and Matt Revis (2-19) led the charge for a Yorkshire bowling attack that skittled their opponents for 83, with only four players reaching double figures and Ollie Pope topping the Surrey scoring with a meek 21 off 44.
Yorkshire, though were subjected to their own skittling straight afterwards as they were bowled out for 82 having been 36-2, with Matt Fisher (6-25) dominating a batting lineup that featured just three players reaching double figures and notching just 46 runs for the final eight wickets.
Surrey - 27-0 in their second innings at close of play - need 158 to win to claim just their second County Championship win of the season.
Former England captain Ben Stokes was the victim of a wonder delivery by Northamptonshire spinner Yuzvendra Chahal on Thursday but responded with three wickets for Durham.
Chahal produced his best impression of the late Shane Warne's memorable 'Ball of the Century' in the 1993 Ashes when the former India bowler sent down a delivery which pitched outside off stump before it spun back dramatically to dismiss Stokes for 14.
Durham were all out for 205, but reduced hosts and Division Two promotion rivals Northamptonshire to 225-7 by the close of day two after Stokes (3-40) led his county's attack with an impressive performance.
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