Nottinghamshire will meet Surrey in the T20 Blast final at Edgbaston on Sunday after convincing semi-final victories.
After Saturday was lost to rain, Finals Day eventually got under way at 15:15 BST on Sunday, with both semi-finals reduced to 11 overs per side.
Surrey won by six wickets with eight balls remaining after Liam Plunkett (3-12) and Reece Topley (2-15) limited Gloucestershire to a modest 73-7.
Notts then flew past Lancashire’s 94-4, with Dan Christian (30) starring.
The Notts captain hit four successive sixes in a five-wicket win that sets up a final which will also be a shortened 16-overs-per-innings match, after the competition went into a reserve day for the first time in its history.
Surrey dominate Gloucestershire
After being put in to bat in the first semi-final, Gloucestershire lost wickets regularly as only three players made double figures, Benny Howell top scoring with 21.
It meant Surrey were able to adopt a steady approach to their chase and, although David Payne (3-18) impressed with the ball, Ben Foakes struck 20 before England Test opener Rory Burns guided them over the line with an unbeaten 12.
In the second semi-final, Lancashire got off to a decent start after opting to bat, thanks to Alex Davies (15) and Liam Livingstone (22), before Steven Croft smashed 33 off 22 balls.
But Nottinghamshire put the brakes on to avoid what had seemed certain to be a three-figure chase, although a fielding injury deprived their reply of opener Chris Nash on his last outing with the club.
It mattered little as Alex Hales hit 29 off 17 balls and, despite a wobble that saw Notts slip from 50-1 to 61-4, Christian smashed Livingstone for four straight maximums to help ensure victory with 16 balls to spare.
Should further rain make it impossible to finish the final, it will be decided by bowl-outs – but good weather is forecast for the rest of Sunday.