Yorkshire claimed a 17-run win over Middlesex on the Duckworth-Lewis method in their Yorkshire Bank 40 fixture at Headingley.
After Middlesex had been restricted to 217-8 from their 40 overs in the Group C encounter, Yorkshire reached 54-0 in 13 overs in reply before a 26-minute break for rain reduced their D-L target to 197 off 35 overs.
And when the rain returned, openers Andrew Gale and Adam Lyth had taken the score to 81 in 17.2 overs, handing Yorkshire victory.
It was Yorkshire's best start in the competition this season, skipper Gale ending unbeaten on 34 from 56 balls with two fours and Lyth 38 off 50 deliveries with three fours and a six.
Leading up to the game, Yorkshire's only success in seven outings had been against Unicorns, their six other matches all being lost.
Middlesex's modest total meant Gale and Lyth were under little pressure when they began the reply and their main concern in the increasing gloom was to make sure that they were always comfortably ahead of the required rate.
Gale led the way for a while but Lyth moved ahead by hooking Toby Roland-Jones for four and cracking his next ball for a flat six over midwicket.
After the first stoppage for rain, the batsmen had sufficient time to make it Yorkshire's best opening stand of the season, overtaking the 61 by Gale and Phil Jaques against Leicestershire at Scarborough, Jaques not being selected yesterday because of an abdominal strain.
Having been put in to bat, most of the action came inside the first nine overs of the Middlesex innings as Paul Stirling lashed a rapid 32 from 20 balls with five fours and a six and paceman Iain Wardlaw knocked over three of the first four batsmen to claim career-best figures of 3-39.
Stirling set the tone by cover-driving Wardlaw's first ball for four and he took seven off the over before tearing into 15-year-old Matt Fisher, striking him for three fours and a six in his initial over to give him the visitors first 25 runs from a dozen deliveries.
Wardlaw, however, replied with a perfect yorker to knock over Stirling's stumps for 32 from 20 balls and end an opening partnership of 42 in five overs with Dawid Malan.
Joe Denly then chopped Wardlaw into his stumps which meant that the seamer had bowled his last five victims in the competition and in the following over Sam Robson suffered a similar fate against Ryan Gibson, whose next two balls were leg-glanced and cover-driven for boundaries by new batsman, Adam Rossington.
It became 65-4 as Malan cut loosely at Wardlaw and was caught behind by Andy Hodd, leaving the Middlesex middle order to rebuild the innings - a job chiefly done by Rossington (42) and Gareth Berg (43) before both became victims of Yorkshire's leading YB40 League bowler Richard Pyrah, who ended up with figures of three for 33.