Essex 199 for 7 (Pepper 75, Lawrence 58) beat Surrey 195 for 6 (Narine 78*) by three wickets
Khushi and Shane Snater had taken five singles from the first five balls of Sean Abbott's final over, to leave Essex needing three to win from the last delivery. Khushi swung hard and high, Jordan sprinted round from long-on to grab the ball as his momentum took him over the ropes but Surrey's captain could not throw it back infield for Overton to complete the catch - and Essex celebrated.
Pepper and Lawrence certainly deserved to be on the winning side, smashing 140 for the second wicket from just 11 overs in a blitz of boundaries that featured nine sixes and 11 fours.
By the 10-over mark Essex were totally in control at 130 for 1 as Pepper, who struck five sixes and six fours, and Lawrence, with four sixes and five fours, entertained a 15,000 crowd in exhilarating fashion.
Surrey's bowlers looked incapable of stopping the carnage, and even West Indies mystery spinner Narine - one of the best T20 bowlers in world cricket - conceded 19 from his first over, the eighth of the innings, as Pepper reverse-swept and straight-drove him for sixes and also swept him conventionally for four.
Lawrence, who has signed to play for Surrey from next April, reached his fifty from 26 balls to Pepper's 24 and launched Narine for one final six from the first ball of the 12th over before falling two balls later to a catch at long-off.
But Pepper fell attacking Jordan in the next over, and Surrey fought back as Paul Walter, Matt Critchley - brilliantly run out by Jason Roy - Daniel Sams, who did swing Sam Curran for six, and Simon Harmer all fell cheaply while Khushi kept chipping away at the runs required. Twenty off three overs finally became eight off the last over - and the 24-year-old Khushi, at the last, prevailed.
Narine also struck seven fours in his own superb exhibition of clean hitting while Roy made 28 from 24 balls on his return to action after almost two months on the sidelines with a calf injury.
Surrey were 57 for 2 after the six-over powerplay, after Essex had chosen to field, with Roy clubbing Sam Cook for a six and two fours - the first an extraordinary scoop past short fine leg - in the fifth over.
Laurie Evans went cheaply, flicking Aaron Beard to deep square leg, but Will Jacks drove the same bowler high and wide of mid-off for four and pulled him for six before being yorked by Cook for 23.
Sam Curran fell to Harmer for only 3 but Narine warmed to his task by smearing the offspinner over the deep midwicket ropes and then lofting Snater straight for another six.
Overton took two sixes in an over off Sams during a quickfire 23, before being caught in the deep, and Narine went on his merry way by thumping Walter's left-arm seamers straight into the Pavilion and then over wide long-on into the Bedser Stand.
Narine finished the innings in style by hitting Sams over the long-on boundary and then clipping the last ball of the 20th over off his stumps to the fine leg ropes.
Essex's reply began badly with Adam Rossington mishitting Sam Curran to mid-on but the England allrounder's next over, the third of the innings, went for a remarkable 31 runs as Pepper began and ended it with sixes and took two fours besides. With a wide, two free hit no-balls and a Lawrence boundary thrown in, the Eagles were suddenly 41 for 1 after just three overs and flying.
Gus Atkinson was then struck for two straight sixes by Lawrence, the second of them from a full toss no ball, as both he and Pepper did as they pleased with the Surrey attack.