Yorkshire collapsed to 81 all out after 15.5 overs before being trounced by 10 wickets as the Birmingham Bears ended a run of three successive defeats in style at Edgbaston.
While the Vikings won the toss, it was one-way traffic after Adam Lyth was bowled for 19 off eight balls by Carlos Brathwaite, who took three for seven from two overs while Craig Miles chipped in with three for 19 from four.
Harry Brook (28 not out from 24 balls) was the only other Yorkshire batsman to reach double figures, with wickets tumbling at the other end, as the North Group leaders were unable to amass anything close to a competitive total.
Adam Hose clubbed six fours and three sixes in his unbeaten 46 off 31 deliveries while Ed Pollock was a capable foil with 33 not out from 23 balls as the Bears overhauled their target midway through the ninth over.
It was a forgettable night for a Yorkshire side depleted by England call-ups and injury, but the Bears moved back into the top four to boost their hopes of qualifying for the knockout stages.
England all-rounder Ben Stokes bowled Northamptonshire Steelbacks pair Ricardo Vasconcelos and Josh Cobb in the same over but Durham were beaten by 30 runs at Wantage Road.
Half-centuries from Vasconcelos (60) and Ben Curran (62), brother of England internationals Tom and Sam, helped Northants to 173 for five after they were invited to bat first, with Stokes finishing with two for 37.
Stokes was then out for a four-ball duck in the reply, with Durham lurching to 11 for four and 48 for six before some lower-order resistance helped them avoid ignominy.
However, Graeme White took four for 26 to become the Steelbacks' all-time leading T20 wicket-taker as Durham were all out for 143 after exactly 20 overs.
Gus Atkinson took three for 21 while Jamie Overton and Gareth Batty chipped in with a couple of wickets apiece as Surrey moved to the top of the South Group after defeating Hampshire by 20 runs at the Ageas Bowl.
Jamie Smith's 59 off 41 balls lifted Surrey to 146 for seven after they were asked to bat first, with Scott Currie taking three for 21, but Hampshire were unable to string together a telling partnership as they fell short, posting 126 for eight from their quota.
