Delray Rawlins shone with bat and ball as Sussex beat Gloucestershire by 51 runs to register their first One-Day Cup victory of the season.
The all-rounder hammered 91 off 62 balls as Sussex totalled 334-9 despite pace bowler Paul van Meekeren's career-best 5-48 for the visitors.
Rawlins then claimed 3-50 with his left-arm spin as Gloucestershire were bowled out for 283 in reply.
In Friday's other two games, there were wins for Hampshire and Derbyshire.
Worcestershire's Ed Barnard followed his 79 in their opening defeat by Kent with an unbeaten 85 against Hampshire, but ran out of partners as they were all out for 192, chasing 236 by the 2018 winners, to lose by 44 runs.
At Chelmsford, Essex were set a target of 319, thanks mainly to a 125-run stand for Derbyshire between Brooke Guest (88) and Mattie McKiernan (72 not out), and were bowled out for 226 in reply.
Sussex chose to bat first at Hove in a game between two sides beaten in their opening fixtures and Harrison Ward (37) and Ali Orr (35) began brightly before the former skied a catch to Ollie Price as he tried to pull a short-of-a-length delivery from Van Meekeren.
The Dutch paceman also bowled Tom Alsop (35) to end a stand of 70 with Cheteshwar Pujara, who after reaching a 57-ball half-century, was stumped by James Bracey off Tom Smith to leave Sussex on 210-5 in the 37th over.
Rawlins, who was dropped 18, and youngster Dan Ibrahim put on 104 in just 10 overs - with Ibrahim taking only 32 balls to reach his maiden List A fifty, nine fewer than his partner.
Ibrahim was caught off Van Meekeren's next delivery but Rawlins hit fives sixes and seven fours before he holed out from the second ball of the final over of the innings.
Gloucestershire's hopes of chasing down such a big target were quickly undermined as they were reduced to 37-3, two of the wickets taken by Aristides Karvelas.
But James Bracey kept them in the hunt with 87 off 86 balls, adding 91 with Zafar Gohar, before Karvelas (3-35) returned to have him caught.
Gohar reached 50 off only 35 balls but when he was lbw to leg-spinner Archie Lenham the task was too much for Gloucestershire, who were all out in the 45th over.
At the Ageas Bowl, Hampshire lost wickets at regular interval through their innings, with only two significant partnerships.
Fletcha Middleton, playing only his second List A match, added 85 with Ben Brown but feathered a catch to the wicketkeeper when he pushed forward to a delivery from Joe Leach (3-41) when one short of 50.
Brown followed for 47 and although Scott Currie hit seven fours in his 43 not out off 27 balls, adding 54 with Toby Albert (19), their score looked a little below par.
But Ian Holland took 3-17 as Worcestershire soon found themselves in disarray on 37-5 in the 13th over.
Taylor Cornall helped Barnard revive their hopes as the pair added 130 before the former Lancashire left-hander was caught at long-on off spinner Felix Organ for 43.
Organ had Leach lbw in his next over as Worcestershire lost their last five wickets for 25 in five overs.
Derbyshire recovered from the loss of four wickets with the score on 117 to push on beyond 300 against Essex.
Luise Reece made 52 off 63 balls before their mini-collapse and Guest and McKiernan provided the rescue act, the former hitting a six and eight fours before he was caught off Shane Snater.
McKiernan took 41 balls to reach 50 - his first half-century in List A cricket - and only needed eight more to progress to 72 before the innings came to an end.
Essex - whose opening group game was washed out - were never really in the hunt despite 43 by debutant Grant Roelofsen, who has been playing club cricket for Billericay.
McKiernan had a hand in their decline, when he deflected a shot by Arron Nijjar into the stumps at the bowler's end to run out Aaron Beard.
Jamal Richards threw the bat for 46 from 44 balls, but the game ended in the 45th over when he hit Mark Watt (2-50) down the ground, but it did not achieve the carry he was hoping for and Anuj Dal ran round to take the catch.
Sunday fixtures (11:00 BST start)
Riverside: Durham v Middlesex
Bristol: Gloucestershire v Somerset
Beckenham: Kent v Hampshire
Old Trafford: Lancashire v Derbyshire
Northampton: Northamptonshire v Essex
Kia Oval: Surrey v Warwickshire
Hove: Sussex v Leicestershire
Scarborough: Yorkshire v Worcestershire