Hampshire 212 for 6 (Vince 76, Fuller 57) beat Essex 209 for 7 (Lawrence 70, Khushi 61, Turner 3-19) by four wickets
It condemned Essex to their third straight defeat and put Hampshire level on 14 points with Eagles with the four-wicket victory, with a superior run-rate.
Chasing 210, Ben McDermott was caught in the fourth over by Paul Walter - which gave him his 13th catch of the season, an Essex T20 record - with Toby Albert also falling in the powerplay. But Hampshire were still on top of the chase, with Vince timing the ball sweetly on his way to a 24-ball fifty.
Joe Weatherley and Ross Whiteley came and went but James Fuller stuck with Vince to keep up with the rate in a 50-run stand. Vince's attempt for a fourth six only picked out safe hands Walter at long off in an over which only went for five runs from Critchley.
If that felt like a turning point, Fuller and Howell swung it back in Hawks' favour with some outrageous hitting and a bit of luck - both were dropped during their time at the crease.
Fuller's fifty came off 27 balls and he celebrated with a huge six over long-on to take the equation to nine off eight balls, although was yorked next ball to end a 63-run stand off 31 balls. But Liam Dawson came in swatted a six first ball with the last three runs coming with four balls to spare.
Lawrence and Khushi seemed to be in a race to reach fifty first, having been stuck in on a stunning pitch and an outfield left worn by the recent Arctic Monkeys gig.
If Lawrence smashed a towering six down the ground, Khushi would hit one further. If Khushi slapped through point, Lawrence would cut one but even harder.
It tied in perfectly with Essex's in-your-face approach to batting - which had seen them lose plenty of powerplay wickets earlier in the competition, but only sent Hawks fielders sprawling on this occasion. There were 73 runs in the first six overs alone, including 21 off Chris Wood's opener.
Khushi is Lawrence's heir apparent to be Essex's middle-order talisman, with both batters similarly wristy and powerful. They both have three fifties in this season's competition and were only split by a ball in their pursuit of the milestone - Lawrence one ball quicker at 25 deliveries.
The 127-run opening stand was Essex's best versus Hampshire in T20s, beating Mark Pettini and Jesse Ryder's 2015 effort by a run before Lawrence was stumped for a 33-ball 70.
Essex continued their collapse with Will Buttleman chipping a reverse lap to point and Simon Harmer was leg-before - Eagles losing six for 55 in the last seven overs having been 154 for 1, but it still reached the sixth-highest T20 score on the ground.