Gloucestershire 178 for 4 beat Sussex 170 for 9
Scorecard Sussex slid to their first defeat of the Friends Provident t20 campaign and missed their chance of setting a new domestic record of 14 successive Twenty20 wins as Gloucestershire caused an eight-run upset under the lights at Hove.
In the absence of their England one-day stars Luke Wright and skipper Michael Yardy, the previously unbeaten South Group leaders blew hot and cold on a chilly night on the south coast - allowing the Gladiators, inspired by James Franklin's career-best 90, to chalk up their second win.
Chasing down Gloucestershire's impressive 178 for 4, Sussex were restricted to 170 for 9 after failing to cash in on two strokes of good fortune early in the reply when both home openers received a life from successive deliveries. Matt Prior saw Hamish Marshall fail to hold on at deep square and then, from the next ball from Steve Kirby, Brendon McCullum was downed by the same fielder at point.
With his dander up, Kirby sent Prior packing for 17 with a yorker, but McCullum made slightly more of his let-off by cracking seven fours and a six in a 28-ball cameo for 46 that ended when he swept a flat catch to Kadeer Ali at deep square leg off the bowling of Vikram Banerjee.
Needing 93 from their last 10 overs, Sussex lost Murray Goodwin to a sliced drive to cover and then crucially big-hitting Dwayne Smith, who lofted to deep square-leg where Marshall made amends for his earlier blunders. Chris Nash, in looking for a single, was run out by bowler Anthony Ireland when following through and, two balls later, Ireland had Andrew Hodd caught behind to finish with three for 35 as Sharks lost their way in their frantic quest for late runs.
Having been inserted by Sharks' acting captain Goodwin, Gloucestershire promoted pace bowler Jonathan Lewis to pinch hit and he responded with three boundaries in 10 balls before being yorked by Chad Keegan. Franklin and Marshall teamed up to post the Gladiators' 50 within seven overs. In a contrasting, little-and-large second-wicket stand worth 91 in 63 balls, it was tall left-hander Franklin who proved the major aggressor.
He hit the first six of the night onto a car bonnet off Will Beer after nine overs and then lofted one from Nash over long-on in the next over to reach his 1,000-run milestone in t20 matches. Marshall improvised effectively, dabbing one from James Kirtley to the third man boundary to take Gloucestershire's total into three figures.
He then crashed a length ball from Smith through cover to move to 37 from 33 balls, only to lose his leg stump to Smith's next delivery. Franklin cracked on to a 32-ball 50 with five fours and a brace of sixes, but lost Chris Taylor when he miscued a pull shot into the deep.
Without once slogging, 29-year-old Franklin continued to make rapid progress with 90 from 50 balls. Unfurling measured, textbook strokes he garnered 11 fours and three sixes - the last of which broke his bat as he dispatched a Keegan slow-ball bouncer out of the park.
Keegan had his revenge in pegging back Franklin's off stump in the penultimate over, yet their testing asking rate of nine an over proved too much for the Sharks