Josh Cobb's team produced a solid performance with the bat to total 171 for six in their 20 overs, and then the bowlers did their bit.
They resricted Somerset to 162 for eight in reply - although there were a few scares near the end thanks an unbroken ninth-wicket partnership of 42 between Roeluf van der Merwe and Ollie Sale that got the visitors a bit too close for comfort!
But Brandon Glover and Ben Sanderson kept their cool in the final two overs to ensure the Steelbacks stay top of the Central Group with five points from three matches.
Adam Rossington was the star turn with the bat for the Steelbacks, crashing 51 from 31 balls, while there was also a solid 42 from skipper Cobb and a crucial late flurry from Saif Zaib, who made 28 not out from just 13 balls
With the ball in hand, Sanderson ended with three for 36 from his four overs, while Graeme White bowled really well to take two for 24 from his four and Gareth Berg took two for 31.
The Steelbacks made one change to the team that hammered Worcestershire Rapids on Saturday, with Berg coming in for Tom Sole.
Sabres, who had yet to play in this season's competition, won the toss and bowled, which was a decision they might have been regretting as the Steelbacks powered to 30-0 in the fourth over.
But they were soon celebrating a quickfire double.
The ball after Stirling had smeared him for six over point, Craig Overton forced the Irishman to edge behind and the Steelbacks opener was out for 15 from 12 balls.
Two balls later and the Sabres were celebrating again, with Richard Levi the unlucky man as he was run out backing up, Overton getting a finger-tip to Cobb's straight drive to deflect it on to the stumps with a backing-up Levi out of his ground.
Suddenly, the Steelbacks were 34 for two and in need of a rebuilding job.
Rossington joined Cobb, and made the most of a life early in his innings when Somerset captain Tom Abell dropped a simple looking catch at extra cover.
Rossington, who was hit a painful blow on the hand by pace bowler Sale, wasn't going to mess about and he went on to flay the Somerset to all parts as he moved to a 50 from just 28 balls, hitting seven fours and one six.
The County had powered on to 115 for two when Rossington eventually perished, picking out Sale at deep square leg to go for 51.
Cobb then took over attacking duties as the Steelbacks continued to make good progress against a very good Somerset attack, and as they moved to 133 for three in the 17th over they were well set for a late charge.
But Sale produced a a brilliant caught and bowled to dismiss Cobb for 42 from 41 balls, and the Steelbacks innings began to stall.
They only added 20 runs from the next three overs, losing Alex Wakely in the process, and when Berg chipped a catch to mid-off off the first ball of Craig Overton's final over, the Steelbacks were looking as thought would come up short at 155 for six.
But Zaib had other ideas, with the little left-hander finding the boundary twice and then producing a remarkable shot to dispatch former England man Overton over extra cover for six off the final ball of the innings.
With the ball in hand the Steelbacks made an early breakthrough as Steven Davies pulled a Ben Sanderson delivery straight to Saif Zaib in the second over, but then the visitors put their foot down.
One Glover over went for 16 as they eased to 54 for one at the end of the six-over powerplay, but the Steelbacks stuck to their plans and were rewarded in the next over as George Bartlett was bowled by Berg to make it 59 for two.
James Hildreth was still going well but he threw his wicket away to leave Somerset on 66 for three, the experienced batsman clubbing Berg to the safe hands of Zaib at square leg.
From being on top. Somerset were now under a bit of pressure, and that would soon be ramped up further as they lost two more wickets in quick succession.
First up, skipper Tom Abell top edged a sweep from Graeme White into the hands of Levi at square-leg, and then Glover produced a snorter that Eddie Byrom could only edge to Ricardo Vasconcelos, deputising for the injured Rossington, behind the stumps.
The Sabres were now 78 for five, on the rack, and needing somebody to come in and play a real innings of substance.
But still the wickets continued to fall, and when Jamie Overton was out in the 16th over to leave the Sabres 116 for eight, the game looked up.
But that innings of substance did eventually come from van der Merwe, who hit 41 from just 25 balls, and he certainly had the Steelbacks panicking as he, along with Sale (14 from nine) kept the scoring rate ticking over.
But with the pressure on in the final two overs, first Glover and then Sanderson did enough to ensure their efforts were to be in vain and seal another win for the Steelbacks.