Worcestershire 177 for 8 (Hose 44, Haynes 32, Finch 30*, Wiese 3-18) beat Yorkshire 175 for 9 (Revis 42, Brown 3-28) by two wickets
The pace bowler made light work of the 19 needed from the final over to earn the Rapids a second win in the space of 24 hours.
Finch set the tone by depositing the first ball from Fisher over the mid on boundary and then the fourth and fifth deliveries also disappeared over the ropes to spark wild scenes of celebration.
The 22-year-old ended with 30 not out from just 10 deliveries as the Rapids squeezed over the finishing line with one ball to spare. He came in at 145 for 7 in the 18th over and struck all but one of the remaining 31 runs required to pull off a remarkable victory against the odds.
It means Yorkshire are still searching for their first win of the season and in all they have gone 11 matches since their last triumph in all cricket last August.
The 38-year-old, who has been playing for Kolkata Knight Riders in the IPL, scored a quickfire 15 but it was his bowling which bamboozled the home side. He mixed up his pace and line to great effect to finish with 3 for 18 from four overs – but then came Finch’s dramatic assault.
Spin accounted for 11 of the Rapids overs with Brett D’Oliveira picking up two more wickets after his 3 for 28 against the Steelbacks while Michael Bracewell and Usama Mir bowled tightly.
The Rapids made one change from the side which had launched the competition with victory away to the Steelbacks, with Dillon Pennington replacing fellow pace bowler Mitchell Stanley.
Yorkshire captain Shan Masood opted to bat but his side were on the back foot after Pennington struck in each of his opening two overs.
Dawid Malan steered the first delivery he faced straight to keeper Ben Cox and Adam Lyth’s mistimed pull lobbed straight into the hands of mid on. It brought back memories of Pennington’s explosive 4 for 0 new ball burst in a Blast game at Headingley two years ago.
Jonny Tattersall and Masood set about trying to rebuild the innings during a partnership of 47 but both fell in successive overs D’Oliveira. Tattersall was pouched at short fine leg sweeping at the leg spinner who then saw Masood hole out off a slog sweep to deep mid wicket.
The spin combination of Mir, Bracewell and D’Oliveira kept the scoring rate in check during the middle overs until Jordan Thompson struck three successive sixes off the latter. He raced to 36 off just 18 balls before aiming another big hit at Bracewell and skying a simple chance to backward point.
Wiese announced himself in impressive fashion with a flat six off Finch over extra cover but then the former Sussex player and Ben Mike both lofted Brown straight to deep mid wicket in the same over.
Revis top-scored with 42 from 31 balls before he was run out in the final over from Brown who then bowled Jafer Chohan after he backed away to the final delivery.
The Vikings carried their momentum into the start of the Rapids innings with a double breakthrough from Fisher. D’Oliveira mistimed a pull and perished just inside the boundary and Bracewell chased a wide delivery and was caught behind.
Thompson broke the partnership after it added 78 when he held onto a fine return catch away to left to account for Hose. Haynes went in the next over from Chohan when he failed to clear deep mid wicket.
Ben Cox clubbed his way to 26 off 14 balls before he turned Revis straight to deep square leg and Ed Pollock aimed a legside blow and was bowled by Wiese.
When Kashif Ali was caught at cover off Thompson, it looked all over for the Rapids but then Finch went into overdrive to secure victory.