But their tense victory on Saturday was almost scuppered by Australian Dan Christian's ignorance of the Laws of Cricket.
Hampshire, who opted to do without Kevin Pietersen after England made the star batsman available, needed one run off the last delivery of the final to beat Somerset on fewer wickets lost.
Christian had called for a runner after pulling a hamstring off the penultimate ball.
But off Zander de Bruyn's last delivery, Christian set off for a leg-bye single as Somerset appealed for lbw.
Jimmy Adams, the runner, scampered through and non-striker Sean Ervine made it safely to the other end. But if the ball had been thrown to wicketkeeper Craig Kieswetter, Christian, despite getting to the bowler's end, could have been run out as he was technically out of his ground.
Both teams made 173 in their 20 overs but Hampshire, who won this tournament for the first time, lost five wickets to the six of Somerset, beaten in the final for the second successive season.
Hampshire were coasting while South Africa's Neil McKenzie was making 52.
But with 11 needed off nine balls, McKenzie was out and panic set in.
However, Zimbabwe all-rounder Ervine's 44 not out -although he was dropped late in his innings by substitute Nick Compton - helped see Hampshire home.
McKenzie, who faced 39 balls, with a six and three fours, told Sky Sports: "There was a lot of chaos out there, I think I caused it towards the end!
"It was really nerve-wracking in the dug-out, there's always a twist."
Veteran Hampshire captain Dominic Cork played a key role. He took two wickets for three runs in a last over of the first innings which also ended the involvement of Somerset all-rounder Kieron Pollard, after a bouncer crept through the grille of the batsman's helmet.
Pollard was later taken to hospital for treatment of an eye injury.
Teenage left-arm spinner Danny Briggs took one for 30 in a Somerset innings where England World Twenty20-winner Kieswetter made 71.
"It was a chaotic last two overs but I'm proud of all the guys here for taking us over that winning line," said Cork. And the 39-year-old former England all-rounder was in a forgiving mood when it came to Christian's potentially match-losing error.
"Maybe Christian could have been run out but the umpires declared it a match won and that's that."
Cork added: "We've been put down a lot of times. "Things weren't going our way in the competition but we just worked hard. We were underdogs all the way through and in the end we just squeezed past."
Somerset captain Marcus Trescothick said in the pressure of the final ball, delayed when the groundsman was summoned to paint an extended crease to take account of the runner, his side had forgotten they could have run Christian out.
"Under pressure you've got to try and keep a cool mind, we just got wrapped up in what was going on," Trescothick said.
As for Pollard, former England batsman Trescothick added: "He's a tough boy, but that was a nasty blow.
"When you take out an international bowler like that it's always going to make a difference to your plans.
"But that last over from Cork really changed things."