Gloucestershire 138 for 9 (Cockbain 40) beat Kent 130 (Smith 3-28, Perera 3-31, Howell 2-12) by eight runs
Gloucestershire moved level on points with south group leaders Hampshire after beating NatWest T20 Blast rivals Kent Spitfires by eight runs in a low-scoring thriller in Canterbury.
Michael Klinger's unbeaten side fielded tigerishly and caught superbly to defend a modest total of 138 for nine on a spin-friendly pitch and complete a T20 Blast double over Spitfires as well as their third successive short-form win on Kentish soil.
Set to chase at almost seven an over for victory, Kent's in-form opener Daniel Bell-Drummond played out a David Payne maiden before crunching 12 off the second over from Matt Taylor, including a leg-side six by Joe Denly and Bell-Drummond's crisp off-drive for four.
Thisara Perera, the experienced Sri Lanka all-rounder, conceded successive boundaries from his first four deliveries of the night as Bell-Drummond raced to 25, but the right-armer struck back by pinning the Kent opener lbw with a quicker, low full-toss as Kent ended their Powerplay on 45 for 1.
Fresh from a career-best 116* at The Oval on Friday, Denly was, on this occasion, guilty of tossing away his wicket by driving a Tom Smith delivery straight into the hands of long-off to spark a dramatic Kent collapse.
Sam Billings opened his shoulders with a back-foot force off Chris Liddle and a pulled six off the same bowler, but his skipper Sam Northeast miscued to extra cover off the wily Benny Howell to leave his side on 68 for 3 after 10 overs.
Jimmy Neesham needlessly slog swept high to mid-wicket to gift the slow left-arm spinner a second wicket then, to Smith's next delivery, Billings was snaffled low down by Klinger at short extra - a catch confirmed on review by third umpire Michael Gough.
Alex Blake plundered the biggest six of the night over mid-wicket to raise Kent's 100 as Smith completed his spell with 3 for 28.
Needing 38 off the last 30 balls, Spitfires lost Darren Stevens caught and bowled to a slower ball as Howell finished with an excellent 2 for 12.
In the dash for late runs Matt Coles was superbly caught on the run at deep mid-wicket by Jack Taylor, who then held another steepling catch at long-off that accounted for Alex Blake.
James Tredwell was skittled in the final over as Spitfires crashed to their second defeat in four starts.
Bowling first after winning the toss, Kent defended their long boundaries well to restrict the visitors to only 13 fours and three sixes.
Neesham struck with his third delivery by having Phil Mustard spectacularly caught off a sliced drive at cover point. On the run and diving forward, Bell-Drummond came up with the ball to make it 18 for one.
Klinger showed his class with the first six of the night in Neesham's next over, a leg-side clip with barely any bat pick-up that sailed over the mid-wicket ropes. He blotted his copybook soon after however, cracking the first ball of the night from Mitch Claydon to Stevens who held an overhead catch at mid-off to send Gloucestershire's dangerman packing for 25 as the visitors reached 42 for 2 at the end of their Powerplay.
Kent turned to spin at both ends in England off-spinner Tredwell and Imran Qayyum, a rookie slow left-armer making only his second Blast appearance. The pair bowled well on a dry pitch, turning the occasional delivery and restricting the boundary count.
Qayyum span one past the outside edge as George Hankins ran down the pitch looking to drive only to be stumped by Billings.
Tredwell finished his four with creditable figures of nought for 25 then, in his last over, Qayyum deceived Ian Cockbain (40) in the flight to have the visiting top-scorer caught at extra cover and finish with 2 for 19 - a stint that included 11 dot balls.
Gloucestershire raised their hundred in the 16th over as Matt Coles wrapped up with nought for 31, but Jack Taylor upped the tempo by taking six and four off successive Neesham deliveries before chipping a Claydon slower ball to mid-off to go for 21.
Perera clubbed to long-on to give Neesham 2 for 30 then, in the final over, Smith, Matt Taylor and Howell were all run out risking second runs into the deep.
Victorious captain Klinger said: "It's slightly easier to be captain when your bowlers perform so well and we fielded like we did. I felt that over all we probably gave a wicket or two too many away in our Powerplay, but our spinners and change of pace bowlers came back really well on a wicket that was quite tough to bat on.
"We talked about 145 to 150 being a par score on that wicket because it was holding and turning, but we've made a name for ourselves over the past few years for being able to strangle batting sides in those positions and luckily enough that's how it worked out for us today. It's always nice to win some tight ones, especially early in the tournament."
Kent skipper Sam Northeast said: "I thought we did really well in the field to keep them below 150, which was our target. We knew it would be tough through those middle periods with the bowlers they have in Howell and Smith. We felt we had enough batting calibre to chase that down and maybe we could have gone harder in the Powerplay, or we could have chosen better options through the middle. It wasn't the greatest pitch in the world but you have to adapt as a team."