Kent 296 for 4 (Bell-Drummond 82, Dickson 68) beat Hampshire 295 for 5(Weatherley 105*, Taylor 56) by one run
Kent bowler Matt Henry kept his cool in the final over to stun Hampshire and hand Kent a sensational one-run victory at the Ageas Bowl.
Henry only conceded two runs in the final over to deny Hampshire - who only needed four off the final six balls.
Joe Weatherley had put Hampshire within a single of keeping up their 100% record in the Royal London One-Day Cup by scoring his brilliant first professional century.
Batsman Weatherley, who spent last season on loan at Canterbury, struck three figures in 99 balls in an incredible 133 run stand with fellow academy star Brad Taylor - who crashed his maiden half century.
Allrounder Taylor had also earlier taken 2 for 35 in an excellent spell, with Kent setting 297, thanks to a late surge, after Daniel Bell-Drummond scored 82.
Opening the batting, Rilee Rossouw failed to replicate his scores of 90 and 111 earlier in the week despite a cameo of 24, including a thumping six.
After a lively opening stand of 54 with Tom Alsop, he slapped a cut to Bell-Drummond at a wide short third man. Alsop, on his first appearance in the tournament, ticked along nicely for 36 before chipping a caught and bowled back to Joe Denly. Two overs later James Vince, having made a decent start, followed when he was bowled attempting a sweep.
Jimmy Adams and Weatherley started to rebuild as scoring appeared to become more difficult but after adding 51 the former miss-hit a straight drive to Sean Dickson at mid-off. Weatherley posted his fourth List A half century, from 59 balls, before seemingly taking the game away with Taylor who fired fifty from 59 deliveries before he was caught at mid-off.
And then Henry pulled off a nail biting final over.
Put in by Vince on a good track under perfect sunny conditions, Kent initially struggled to get going, scratching 37 off the first 10 overs. Despite the steady scoring, Kent and in particular Bell-Drummond steadfastly protected their wickets, although Zak Crawley was undone by a superb ball by Taylor.
Offspinner Taylor produced a miserly spell, bowling his 10 overs straight through, with a straight six the only boundary scored off him. His temperament was rewarded with a second wicket when a frustrated Denly picked out Alsop on the long-on boundary.
Heino Kuhn patiently accumulated 25 before Bell-Drummond pummelled a straight drive into his arm at the non-striker's end, after a short period of medical decided to retire hurt.
Amongst the wickets and injury, in form opener Bell-Drummond had amassed a quality 82, including bringing up fifty in 69 balls, to steer his side to a comfortable four and a half runs an over before he was narrowly run out by a Mason Crane direct hit.
Kent looked set for a modest total, but Alex Blake, Sean Dickson and Darren Stevens smashed them above par with a mixture of canny shot selection and good field splitting in a stunning final 12 overs.
Blake and Dickson slammed 67 runs from 43 balls, the former taking a liking to Crane by plundering him for a pair of sixes, but the legspinner won the overall battle when a reverse sweep found Weatherley on the square-leg boundary.
At the other end, Dickson belied his List A strike-rate of 72 to pump a half century from 35 balls, eventually ending unbeaten on 68. He added another 57 in 31 deliveries with Stevens for an unbroken fifth-wicket to take the visitors to 296.