A run-a-ball century by Mark Pettini helped Essex to a 25-run victory over Worcestershire in the CB40 Group A match at New Road.
The Eagles opener smacked 111, with three sixes and seven fours, as his side piled up an impressive 269-4 after being put into bat.
Worcestershire were then restricted to 244-8, despite a battling 68 from Phil Hughes.
It enabled Essex to register their second Group A victory of the season and gain revenge for a seven-wicket defeat against the Royals at Chelmsford in May.
Pettini was in dazzling form and was solidly backed up by 62 from Tom Westley and a stunning unbeaten 50 off 24 balls from Ryan ten Doeschate, who punched four sixes and three fours.
Essex, despite Westley offering a couple of difficult chances to James Cameron, made an excellent start to their free-scoring innings.
He and Pettini completed a half -century stand in nine overs before Westley went on to register his 50 off 47 balls with one six and seven fours.
His fine efforts, coupled with Pettini's eyecatching progress, enabled Essex to confidently move past the three-figure mark in the 19th over.
Pettini went on to notch his 50, containing one six and two fours off 62 balls, before Westley was run out to a direct throw by Brett D'Oliveira from gully for 62.
He hit one six and seven fours off 60 balls and put on 113 in 20.3 overs with Pettini, who had a lucky let-off when he was dropped on the boundary by substitute fielder Matt Pardoe.
Pardoe only succeeded in pushing to ball over the rope for six to enable grateful Pettini to move into the seventies.
He went on to add 65 in 11 overs with Owais Shah, whose dismissal for 28 paved the way for Ten Doeschate to set about some poor Worcestershire bowling.
Captain Pettini eventually fell to a catch by Daryl Mitchell at wide mid-off off David Lucas to leave Ten Doeschate to continue his 33-minute assault.
Worcestershire tried hard to get to grips with their formidable run chase, but in the end tumbled to their fourth CB40 defeat on the trot.
Vikram Solanki (seven) and Moeen Ali (42) had both been removed before the hosts reached the halfway mark in their innings on 100 for two with Hughes and Cameron both fighting to keep in touch with the target.
Their 52-run stand ended when Cameron (29) was run out going for a hesitant single.
After Mitchell (one) and Neil Pinner (15) had been removed, Hughes and Gareth Andrew did their best to gather momentum.
But once Andrew (32) was ousted, the writing was on the wall for Worcestershire - despite Hughes' knock which contained one six and four fours off 75 balls.