Simon Harmer and Ravi Bopara starred as Essex were crowned Vitality Blast winners for the first time after toppling defending champions Worcestershire by four wickets in a final that was decided off the last ball.
Harmer was the standout bowler in a crowded field on Finals Day, taking three wickets for 16 runs in the showpiece as Worcestershire were restricted to 145 for nine after being invited to bat first at a sold out Edgbaston.
Bopara kept Essex's hopes alive after they had lurched to 82 for five in the 14th over with a breezy 36 not out from 22 balls, before Harmer appropriately registered the winning boundary from the final delivery of the match.
With two needed from the final ball and the field in close, the Essex captain (18 not out) steered Wayne Parnell through point for four before setting off in celebration as his team-mates attempted to catch him.
Victory marks the start of what could be a memorable few days for the club, who only need to avoid defeat at Somerset next week to clinch the Specsavers County Championship pennant.
Worcestershire were seeking to become the first team to successfully defend the domestic English Twenty20 title and would have fancied their chances when Essex required 23 from the final two overs and 12 from the last six balls.
Parnell had been instrumental in Worcestershire's nerve-shredding one-run over Nottinghamshire in the semi-final but he blinked first here as his penultimate delivery was hammered back over his head by Harmer, who then completed the job.
On a surface where spin and pace off the ball were a major theme throughout Finals Day, Harmer's figures across his side's two fixtures were an astonishing seven for 35, having underpinned their 34-run win against Derbyshire with a four-wicket haul.
His decision to field first looked to have backfired when opposite number Moeen Ali crunched three fours and two sixes in his 32 from 26 balls as part of a 56-run stand alongside Riki Wessels.
But Harmer made the breakthrough with a fantastic return catch to see off the England all-rounder one day after he announced he was taking a break from Test cricket after losing his red-ball central contract.
Harmer had two in two when Ben Cox was adjudged lbw first ball although replays showed last year's man of the match was outside the line and had inside edged a sweep on to his pad.
From that point Worcestershire were unable to wrestle the initiative back from Essex's coterie of spinners and slower bowlers, with scoring opportunities limited.
Wessels attempted to anchor the innings but was run out for 31 while there were useful cameos of 19 from both Parnell and Daryl Mitchell, while Bopara claimed two wickets in the final over of the innings.
Worcestershire's total was swelled by 11 wides and, having defended 147 for nine in nail-biting fashion against Nottinghamshire, the Pears may have felt they had posted a competitive total.
Tom Westley underpinned Essex's early reply with 36 but was caught by Pat Brown running in from deep square-leg from a top-edge off Parnell.
Moeen had held himself back until the middle overs, alongside the usually parsimonious Brown and Parnell, which seemed to be decisive when the Worcestershire captain snared Dan Lawrence and Ryan ten Doeschate.
The required run-rate was up to 10 with six overs remaining, which seemed to be beyond Essex on a day where the highest score was the 160 for five they had set earlier in the day.
Bopara, though, settled to his task with back-to-back fours off Ed Barnard while he crunched timely sixes off Moeen and Brown before deferring to Harmer as the match reached its crescendo.