Tasmania 4 for 239 (Bailey 67, Silk 59*, McDermott 58) beat New South Wales 237 (Nevill 56, Ellis 5-38) by six wickets
Nathan Ellis claimed his maiden five-wicket as Tasmania hauled themselves off the foot of the Marsh Cup table by overturning a star-studded New South Wales side at North Sydney Oval.
Ellis, who made his Western Australia debut at the start of the competition, claimed 5 for 38 as New South Wales were bowled out for 237 with almost seven overs remaining.
They had been set back early in the day when Riley Meredith continued his good time in Sydney by removing David Warner and Steven Smith inside the first six overs to follow the five-wicket haul he claimed in the Sheffield Shield match.
On a small ground with a fast outfield New South Wales needed their international attack - featuring Pat Cummins and Josh Hazlewood in their first matches of the season - to pull the game out of the bag, but Ben McDermott warmed up for his return to Australia's T20I set-up with a crisp half-century.
McDermott began the chase by taking 12 off Mitchell Starc's opening over with three drives and in all 46 off his 58 runs came in boundaries before he was bowled attempting a reverse sweep off Nathan Lyon.
He had formed a brisk opening stand of 61 with Caleb Jewell to set Tasmania on their way in the chase until Jewell was bowled off his pads by Hazlewood as he walked across the crease. Hazlewood returned to trap Beau Webster lbw to give New South Wales a glimmer with Tasmania 3 for 113.
From there, however, the stand-in captain Jordan Silk - covering from the injured Matthew Wade - and George Bailey eased towards the target with a stand of 118 in 21 overs. Bailey, who was left out of the Sheffield Shield match, moved to fifty from 59 deliveries and Silk matched that with a top-edged six off Cummins who recorded none for 62 off his 10 overs.
Tasmania had put New South Wales into bat on a ground where it is difficult to defend. Meredith struck in his second when Warner toe-ended a pull back to the bowler and then again in his next when Smith clipped straight to square leg, to the disappointment of himself and the crowd that had come to watch in anticipation.
Silk produced an excellent piece of fielding with an under-arm flick to run out Moises Henriques after Daniel Hughes called a risky single and Hughes became Ellis' first wicket when he was given caught down the leg side.
Matthew Gilkes gave another glimpse of his talent with some glorious shots in a better than run-a-ball 43 before driving a catch to cover. The lower all managed to chip in alongside captain Peter Nevill but couldn't transform the innings as Ellis hit the stumps four times, the delivery take Cummins off stump being especially eye-catching.
The defeat all-but ends New South Wales' hopes of reaching the final.