Surrey 188 for 8 (Sibley 61, Finch 56) beat Essex 186 for 6 (Bopara 75, T Curran 3-28) by two runs
Tom Curran kept his head in the final over to carry Surrey to a sensational two-run victory in the opening NatWest T20 Blast game of the season at Chelmsford.
With Essex requiring 10 off the last six balls, and six wickets in hand, Curran claimed the key wickets of Ravi Bopara and Ashar Zaidi to claim a memorable victory.
Bopara's dismissal off the second ball of the over ended a 46-ball 75, with five sixes, that looked to have put Essex in the driving seat.
Earlier Dominic Sibley thumped four sixes in a swashbuckling 61 that enabled Surrey to post a challenging total of 188 after being put in to bat.
However, it had looked as though sixes from successive deliveries bowled by Jade Dernbach in the penultimate over by Bopara - one straight, the other over long leg - meant Essex needed less than two runs a ball from the final over.
The first ball went for two, but Tom Curran found the extra pace to beat Bopara from the next. With five required off two balls, Curran added the scalp of Ashar Zaidi, bowled to a full-length ball. The boundary required from the final ball as beyond James Foster.
Essex had reached 25 in the third over when Varun Chopra left alone a delivery from Tom Curran that pitched outside off-stump and hit middle and leg.
Dan Lawrence, who had hit Sam Curran straight for six, followed soon after when he swished inelegantly at the younger Curran and was caught behind for 13.
Tom Westley and Ravi Bopara put on 45 for the third wicket in six overs. But Westley was undone by Scott Borthwick's first ball, which spun in and bowled him for 23. He had earlier edged Ravi Rampaul for six backward of square and then carted Dominic Sibley over cow corner for a second.
Bopara hit Jade Dernbach for a straight six, pulled Rampaul for a second and hooked Borthwick for No3 as Essex accelerated. Rampaul went for 16 from one over, Borthwick for 14 the next as Bopara and ten Doeschate made hay.
Bopara scrambled a single into the offside to reach a 43-ball fifty, but the partnership was broken by Sam Curran who trapped ten Doeschate lbw on the front foot. Essex still needed 52 from 26 balls, and 25 from the last two overs.
Surrey lost Jason Roy to the fourth ball of the game, lbw to one from Mohammad Amir that swung late, and wickets followed in quick succession throughout, bar a sixth-wicket stand of 55 between Dominic Sibley and Sam Curran.
Replacing Amir, two of Paul Walter's first four deliveries were wayward and signalled as wides, but his third legitimate ball arrowed past Mark Stoneman's bat and took out middle and leg stumps.
Finch had already laid into Jamie Porter with a four through midwicket and a six over long leg off successive balls, and was similarly severe on Ashar Zaidi with a four chipped to deep extra cover followed by another six into the second tier of the stand at long leg.
But Zaidi had the last word in his first over, tempting Rory Burns into a reverse sweep and bowling him.
Finch reached his fifty from 23 balls with his third six, slogged-pulling Zaidi high over midwicket. But four balls later, in trying to work Bopara down to third man, the Australian top-edged behind for 56.
Bopara had a second wicket in his third over when Ollie Pope pulled him to the midwicket boundary where Amir leapt to catch. Surrey had lost half their batting for 86 inside 11 overs.
The fifty partnership for the sixth wicket came off 28 balls, before Curran on 25 gave himself room against Walter and lost his leg stump. Sibley lost the other Curran, Tom, to an inswinger from ten Doeschate's first ball.
Sibley reached a valiant half-century from 35 balls with his fourth six, but departed for 61 when he was run out off the last ball. Borthwick had his stumps shattered from a free-hit off Walter, but James Foster had a stump out of the ground before Sibley made his ground.