Kent 111 for 7 (Tredwell 42*) beat Worcestershire 110 for 9 (Coles 4-20) by three wickets
Kent moved joint top of Group A following a nervy three-wicket win over Worcestershire in a game reduced to 25 overs per side due to rain.
Chasing 111 for victory under the lights in Canterbury, Kent slumped to 45 for 6 as Worcestershire scented their second win. But a 47-run seventh wicket stand between brothers-in-law Geraint Jones and James Tredwell bailed Kent out of trouble and saw them to the cusp of a victory they ultimately secured with 11 balls to spare.
New captain Tredwell held his nerve and timed the ball sweetly for his unbeaten 42 from 40 balls, while Jones contributed 30 as Kent claimed their third win in four YB40 starts.
Kent made an inauspicious start to their run chase when Sam Billings skied a return catch to Jack Shantry, the left-arm seam bowler, who then won an appeal for leg before against Brendan Nash as he aimed to clip an inswinger through midwicket. Darren Stevens checked a lofted drive against Gareth Andrew to clip an overhead catch to the bowler then another inducker from Shantry trapped Ben Harmison leg before for a fourth-ball duck.
The home collapse continued when Rob Key pushed inside the line of a Daryl Mitchell offcutter and the Worcestershire skipper celebrated a second success when Adam Ball drove a low catch to mid-on to depart for a second-ball duck and bring Jones and Tredwell together. They rebuilt the innings before Tredwell, who struck six fours and a six, saw Kent to victory in the company of Matt Coles.
Earlier, Worcestershire batted first after losing the toss and, following a 140-minute delay for rain and mopping up, made the worst of starts when Moeen Ali fell to only the second ball of the game without scoring. Working to leg against a Mark Davies delivery that held its line against the slope, the ball caught the leading edge of Ali's bat and flew to Nash at backward point.
With 13 on the board Mitchell fenced at a lifting delivery from Coles to edge to first slip and give Coles the first scalp of his evening's return of 4 for 20.
Sri Lanka Test star Thilan Samaraweera crept into double figures before he fell to the first of two stunning catches. Clipping off his legs toward deep midwicket, Samaraweera watched as fielder Billings, back-pedalling toward the boundary rope, caught the ball then immediately tossed it into the air before re-crossing the boundary to reclaim the catch on his return to the outfield.
Alexei Kervezee, Worcestershire's top-scorer with 27 from 31 balls, perished to an even better catch that made it 50 for 4. Slicing an attempted straight drive, Kervezee saw Ben Harmison throw up his right arm when running back toward the pavilion to claim a dramatic one-handed catch as the ball dropped over his right shoulder.
Davies snaffled another sharp catch at mid-off to account for Neil Pinner, then Coles returned to demolish the stumps of Andrew and have Ben Cox caught at long leg from a pre-meditated paddle sweep. Brett D'Oliveira was run out attempting a second to long on, but 10th-wicket partners David Lucas and Shantry at least batted out the overs leaving Kent to chase at 4.44 an over for victory.