Gloucestershire 275 for 8 (Klinger 134, Coles 4-57) beat Kent 264 for 9 (Bell-Drummond 90, Dickson 50, Liddle 5-36) by 11 runs
Chris Liddle turned Gloucestershire's Royal London Cup tie against Kent on its head as they claimed an unlikely win over Kent by 12 runs in glorious Bristol sunshine.
Michael Klinger's 134 looked to have paved the way for a challenging Gloucestershire total after they have been asked to bat first. But a flurry of late wickets saw Matt Coles finish with 4 for 57 and hosts restricted to 275 for 8, no more than a par score in the conditions.
It didn't look like enough as Daniel Bell-Drummond followed up his tons against Somerset and Sussex with 90 off 108 balls. With Sean Dickson and Sam Northeast lending good support, Kent looked to be cruising.
But Liddle had other ideas and, from 200 for 2 in the 39th over, he bowled a telling spell from the Ashley Down Road End as the visitors collapsed spectacularly, closing on 264 for 9.
The win was Gloucestershire's second in the competition and kept alive their slim hopes of a top three finish in the South Group, while Kent must accept elimination before the knockout stage, having won only one of their first five games.
Gloucestershire head coach Richard Dawson said: "It wasn't until late in the day that I felt we had a chance of winning. I'll take the victory even though I'm not quite sure how it happened.
"It was a battle and Chris changed the game with one spell. He varied his pace really well was smart in how he bowled his cutters.
"We kept going and once we got a sniff we were good enough to capitalise on it. It keeps us in the competition and makes Friday's home game with Somerset even more appetising."
Klinger could hardly have done more, reaching his 16th List A hundred off 123 balls to help take the home side's score to 260 for 3 before he was out.
The 36-year-old Australian hit three of his sixes into the flats at the Ashley Down Road End of the Brightside Ground, his favourite one-day shot at the venue, and progressed with increasing assurance on an excellent batting pitch. Chris Dent and Ian Cockbain shared useful partnerships, but when Klinger was caught at deep mid-wicket off Joe Denly it signalled a rapid transformation in fortunes.
Far from building on their captain's efforts with some big hitting at the end, Gloucestershire lost five wickets in less than two overs as Coles and James Harris put themselves on hat-tricks.
With the sun still shining in a cloudless sky, a target of 276 did not appear looked likely to test Kent's strong batting line-up.
They lost Joe Denly to a careless shot off Liddle with the total on 64, but Bell-Drummond, who survived a couple of early scares, and Dickson then put together a stand of 89 in 17.3 overs.
Dickson perished the ball after reaching a 62-ball half-century, picking out George Haskins at deep mid-wicket to give left-arm spinner Tom Smith a wicket. By the time Bell-Drummond was brilliantly caught low down by Klinger at extra-cover off Liddle, Kent had posted 200 and needed a further 76 from 11.4 overs.
Northeast was established and playing well. His fourth six, over long-on off Jack Taylor was one of the biggest of the match.
Darren Stevens was visibly angry with himself when caught behind off Liddle trying to run the ball down to third-man and at 217 for 4, Kent were suddenly far from comfortable.
Soon it was Northeast trudging back to the pavilion having smashed Liddle straight to long-on where Jack Taylor took the catch. From looking in total command, the visitors were suddenly under pressure at 220 for 5.
More poor shots accounted for Matt Coles and Alex Blake and Gloucestershire sensed their chance. The Kent tail-enders flailed wildly without success and the game headed for an unlikely outcome.