Gloucestershire 289 for 6 (Roderick 87*, Hankins 77) beat Essex 287 for 7 (Zaidi 82, Liddle 4-57) by four wickets
Gareth Roderick posted a superb 87 not out as Gloucestershire beat Essex by four wickets in Bristol and register their second victory in three days in the Royal London Cup South Group.
Ashar Zaidi top-scored with 82 as Essex raised a competitive 287 for 6 on a decent batting track after winning the toss.
But Roderick produced a true captain's innings, staging a match-winning sixth-wicket partnership of 79 in seven overs with the hard-hitting Ryan Higgins as Gloucestershire reached their target with 11 balls to spare.
Playing only his fifth List-A game, Academy product George Hankins registered a second white-ball half century inside three days, producing some clean hitting to accrue seven boundaries in a crowd-pleasing innings of 77 from 98 balls.
Although he dragged a wideish delivery from Ravi Bopara onto his stumps eight runs short of his highest score, he nevertheless provided Gloucestershire's reply with solid foundations.
Simon Harmer kept Essex in the hunt, accounting for danger-men Ian Cockbain and Jack Taylor with his off spin, but Gloucestershire held the upper hand while Roderick remained at large.
Demonstrating a cool head, Gloucestershire's captain combined deft placement with feverish running between the wickets to raise 50 from 55 balls before pressing the accelerator button. Higgins provided rich entertainment in a murderous innings of 47 from 29 balls, accruing three fours and three sixes to break Essex spirits.
Openers Adam Wheater and Varun Chopra had earlier afforded the Eagles a flying start, taking advantage of some loose bowling to raise 74 in 12 overs.
But Gloucestershire quickly redressed the balance, slow left armer Tom Smith pinning Wheater lbw with his first ball, and then taking a superb diving catch at mid-off to remove Tom Westley without scoring before inducing Dan Lawrence to loft a miscued drive to mid-on.
When Chopra flashed hard at a wide delivery from Chris Liddle and was caught at point for 42 in the 17th over, Essex had lost four wickets in 33 balls and were teetering at 93 for 4.
Charged with the task of rebuilding the innings, Bopara dominated stands of 47 and 57 with Ryan ten Doeschate and Zaidi for the fifth and sixth wickets respectively. Having grafted 50 from 70 balls, he chased a ball outside off stump and was caught behind to become Liddle's third victim.
Zaidi picked up the cudgels thereafter, striking seven fours and two sixes and adding 90 for the sixth wicket with Harmer to propel the visitors to a competitive total.