A superb batting performance helped Westbury end Launceston's run of two straight T20 titles at the NTCA Ground on Thursday.
Launceston recovered from 4-47 to post 5-123, but could not quell an early onslaught from Jesse Digney as Westbury cruised to a six-wicket win inside 18 overs.
The big-hitting opener was in the mood for sixes and dispatched consecutive balls into Dowling Street's Toll carpark on his way to 38 off 29.
Play stopped for several minutes as fielders retrieved the first six, only for the next delivery to wind up in the same location.
Shamrocks captain Dan Murfet anchored the chase with a calm 26 while Jono Chapman (35) registered a maximum of his own in an unbeaten 47-run stand.
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"I think we're really happy with the outcome, we knew it'd be tough," Murfet said.
"Jesse's a massive X-factor for us in all forms of cricket - he has a really good ability to hit the ball and a pretty solid defence at the same time."
Earlier, Ben Humphrey had almost single-handedly steered the Lions to a competitive total with a splendid 61 not out.
The lanky all-rounder put on 55 with Will Bennett, who was playing his third T20 of the day, after the Lions' top three all hit catches to cover.
Nathan Parkin's diving effort to end an ominous cameo from Sam Elliston-Buckley proved particularly valuable while Jake Lloyd took the big scalp of Alistair Taylor on his way to 2-11.
Wesbury's chase began with a bang as Chathura Athukorala, who had earlier pulled up sore three balls into his first spell, clouted three fours off the first over before snicking off.
An intriguing battle between Humphrey's clever changes of pace and Digney's fireworks then landed in favour of the latter as a flurry of boundaries set the Shamrocks up for victory.
The T20 flag - which surprisingly came as only Westbury's second - followed a rollercoaster weekend where the Shamrocks lost to Launceston in a super over and finished day one bottom of the table before qualifying for the final on net run rate.
Thursday's victory marked an end to Launceston amazing 12-0 start to season 2020-21 and sets the Shamrocks up for a charge at Greater Northern Cup and Cricket North three-peats.
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"It's a positive - at the end of the day there's three pieces of silverware up for grabs at the start of the season and we've got our hands on the first one," Murfet said.
"We know fine well there's bigger things on the horizon that we could look to at the end of this year, but this is a massive tick in the box along the way.
"We'll make sure we enjoy this win - [the T20 cup] is something in the past we haven't been too successful at even though we've had plenty of success in recent years so it's good we can get that one away.
"I think we'll take a lot of positives out of getting over Launceston as well with the season they're having - we'll take a lot of confidence out of getting over them in a final this early in the season."