Middlesex 161 for 5 ( Eskinazi 47, Stirling 44, Voges 38) beat Gloucestershire 100 (Howell 34, Taylor 31, Finn 4-24, Helm 3-14)
Steve Finn, with a display of fast and aggressive bowling, led Middlesex to victory over Gloucestershire by 61 runs at Uxbridge on Tuesday evening to keep alive his side's rather far-fetched hopes of reaching the quarter-finals of the NatWest Blast.
Finn had figures of 4 for 24, his best in the competition, and he was excellently supported by Tim Southee, who took 3 for 9 from three overs.
Middlesex's heavy win did wonders for their net run rate and propelled them from bottom to third in the table with one game remaining - although Essex, Kent and Surrey all have a game in hand.
Eoin Morgan, Middlesex's captain, said: "Our bowling performance today was the best of the tournament so far. And that was after we had shown a lot of skill and maturity with the bat. You don't want to peak to early in this competition. We'll take this confidence to Cardiff on Friday for a crucial match."
Gloucestershire, chasing a target of 162, lost their talisman when Southee had Michael Klinger caught at slip by Adam Voges with only the second ball of the innings.
Then Finn, showing the pace and menace that has seen him make 126 appearances for England across all formats, struck with the first and final deliveries of his second over.
First he bowled the dangerous looking Ian Cockbain with a devastating yorker and then Cameron Bancroft, attempting to keep the ball out of his stumps, played on.
By the end of the next over, the fifth, Gloucestershire already looked out of it at 25 for 5. Tom Helm bowled Phil Mustard with a slower ball and then, with his next delivery, he had Kieran Noema-Barnett caught at mid-off by Southee, again with a slower ball.
At 56 for five at the halfway stage of their innings Gloucestershire still looked well beaten. But then Benny Howell hit a vast six over mid-on as 13 came from Nathan Sowter's over. And ten came from the next, bowled by Ryan Higgins, who was hit over midwicket for six by Jack Taylor.
But then Finn, returning to bowl his last over, made two crucial breakthroughs. He had Taylor caught down the legside for 31 and then, two balls later, had Howell caught off a skier to the keeper.
When Southee struck two blows with successive balls in the next over the contest really was over.
Middlesex were heavily dependent on a fourth wicket stand of 66 in seven overs between Stevie Eskinazi and Voges for what remarkably was their first T20 win over Gloucestershire.
Eskinazi took time to play himself in but then struck a 39-ball 47, with three fours and the first of only two sixes in the Middlesex innings, struck high over midwicket off Graeme van Burren in the 17th over.
Voges made a classy looking 38 from 27 balls, with three fours. The batsmen were out in successive overs towards the end of the innings.
They lost their first wicket in the fourth over when John Simpson sliced David Payne to Ian Cockbain at backward point. But that was also the over in which Paul Stirling really launched the Middlesex innings, pulling, driving and then sweeping Payne's final three deliveries for fours. At 75 for 1 after ten overs Middlesex had the basis of a challenging total. But Stirling, who had hit six fours in his 31-ball 44, was caught on the deep midwicket boundary off Tom Smith off the first delivery of the 11th over.
Smith struck again two balls later when he dismissed Eoin Morgan, reverse sweeping, for a duck before Eskinazi and Voges pulled the innings round.