A 185-run third-wicket partnership carried Essex to victory over Notts at Trent Bridge.
Notts’ total of 218 was surpassed in the 44th over, as Robin Das and Noah Thain’s partnership destroyed any early momentum that Rob Lord found by taking two early wickets.
Matthew Montgomery top-scored for the Outlaws with a composed 52.
After losing the toss, Ben Slater and Jack Haynes accumulated steadily through the first eight overs before the latter was caught behind for 17.
Slater was joined by Freddie McCann, and the pair reached their 50 partnership off 55 balls Slater heaving Allsion for six in the 18th over.
But Slater departed just three runs short of his half-century when he was caught at point by Feroze Khushi.
Haseeb Hameed was bowled by Jamal Richards, but Matt Montgomery got off to a brisk start before he lost his partner, McCann caught behind off the bowling of Richards for 33.
Tom Moores added a quickfire 33, including four fours and two sixes before he was caught on the boundary as he sought to increase the run-rate.
Despite Essex continuing to make inroads, Montgomery remained resolute, reaching his half-century off 66 balls before being caught on the boundary for 52
Rob Lord's departure saw Jamal Richards complete his five-wicket haul, the Outlaws setting Essex 219 to win.
With Luke Fletcher having made a typically miserly start to the Powerplay, it was Lord who broke through. Luc Benkenstein pulling the paceman to Jack Haynes, who enacted an acrobatic catch on the boundary's edge, throwing the ball up as he went over the rope before holding on for a second time.
Lord then picked up his second by removing Tom Hartley’s off-stump with a peach of a delivery as he departed for 13.
But Thain and Das moved Essex into the driver’s seat as they rebuilt, moving to 50 within five overs of each other.
Both Fletcher and Liam Patterson-White saw the ball fly past the edge on a few occasions after the halfway stage but the Essex pair continued to slowly hunt down the Outlaws’ target.
Thain and Das then decided to step on the gas as they accelerated their chase and found the boundary more frequently.
With ten overs remaining and with their third-wicket partnership standing at 157, Essex needed just 33 runs, but Calvin Harrison did secure a scalp as he trapped Thain LBW for 83.
But it was Das' day, as he reached his century with the final ball of the chase to secure a seven-wicket win.