Alex Davies led Lancashire home with an unbeaten 75 as the runaway North Group leaders beat Northamptonshire by eight wickets at Wantage Road.
The rain left Northampton by mid-afternoon and the visitors took advantage of a full match to extend their lead at the top of their Vitality Blast group to five points with four matches remaining.
Davies had been short of form in the competition but got the chase off to a perfect start with three consecutive boundaries off Ben Sanderson. He then swept Graeme White's final ball of the seventh over, one of eight boundaries in his seventh T20 half-century.
Davies' running between the wickets was sublime, with many scampered twos. Later in the chase, captain Dane Vilas joined in the dashing, taking two straight to third man in what proved to be the final over.
Vilas, like Steven Croft before him, arrived after Northamptonshire had been offered a little hope and immediately kept the chase right on track with clever batting.
He struck the winning boundary through the legs of Alex Wakely at deep square as Lancashire eased home with nine balls to spare.
Liam Livingstone played his part with 22 in 10 balls, slamming Nathan Buck's first ball over long-on for six and carving a boundary over cover before holing out to deep midwicket.
Croft made a run-a-ball 27, showing great wrists to work the bowling around, before being yorked by Faheem Ashraf.
The hosts fell to a fourth defeat but still remain in the mix for qualification with five games to play. Here, having been sent in, their 157-7 always looked short.
Richard Levi pulled and flicked James Faulkner for two boundaries in the opening over and then pulled Saqib Mahmood for a third four, but trying to flick Faulkner as he changed ends the opener got a leading edge to third man to fall for 18.
Josh Cobb then dragged his sixth ball to deep square to fall for a duck as the Steelbacks finished the powerplay on 41-2.
Adam Rossington provided some momentum. He pulled his first ball for four and whipped Danny Lamb wide of deep square to end the 10th over with another boundary. But trying to target Livingstone's leg-spin, he picked out long-on and fell for 40 in 32 balls.
The home side were 104-4 after 16 overs but gained some momentum as Dwaine Pretorius swung Matthew Parkinson over long-on and deep midwicket for sixes and Rob Keogh also cleared the fence as 29 runs came in the 17th, 18th and 19th overs.
But Faulkner went for only four, and took two wickets, in the final set and Lancashire's batsmen backed the effort up in some style.
However, South Group matches between Essex and Middlesex and Kent and Glamorgan were abandoned without a ball bowled due to persistent rain.