Kane Williamson hit a century and Chris Dent claimed four wickets as Gloucestershire crushed Group A rivals Leicestershire by 164 runs.
New Zealander Williamson's career best one-day score of 112 helped the hosts post a total of 294-6 in the Clydesdale Bank 40 clash at Bristol.
Benny Howell provided excellent support, making 88 from just 82 deliveries during a third-wicket stand of 152. The 23-year-old blasted nine fours and a six before being stumped by Ned Eckersley off Robert Taylor.
Alex Gidman (24) and Ian Cockbain (25 not out) offered contributions in the closing overs to help the Gladiators set their opponents a tough target.
It turned out that Leicestershire's didn't get anywhere near to the 295 they required, mainly due to part-timer Dent taking career-best figures of 4-43.
His off-spin proved too good for the majority of the Foxes' middle order, Ramnaresh Sarwan one of his victims when he caught by Hamish Marshall after labouring his way to 18.
At one stage the visitors were 74-6 before Taylor and Claude Henderson offered some late resistance, making 29 not out and 22 respectively.
However Irish seamer Graeme McCarter (3-15) returned to claim the final two wickets, Leicestershire being bowled out for just 130 with 9.3 overs to spare.