Worcestershire booked a home semi-final against Nottinghamshire or Kent in the Royal London Cup by seeing off arch-rivals Warwickshire by one wicket in a real nail-biter at Edgbaston.
Joe Leach's side staved off a late fightback by the Bears to secure the narrowest of victories - and top spot in the North Group.
Chasing Warwickshire's 292, Worcestershire seemed cruising when they needed 21 from 11 overs with five wickets in hand.
But they ended up scrambling home by one wicket as Dillon Pennington (three from 20 balls), on his first-team debut, and Ed Barnard (13 not out from 14), added surely the first partnership of nine runs in five overs ever to be decisive in a List A game.
Put in, Warwickshire totalled 292 for seven as the visitors bowled well early on with only Sam Hain (68, 84 balls, eight fours), of the Bears' in-form top order, staying long. Only a partnership of 133 in 19 overs between Tim Ambrose (75, 73 balls, six fours) and Will Rhodes (69, 56 balls, nine fours) kept the Bears in the game.
Worcestershire's reply was then given a lightning start by Moeen Ali's 11th List A century. Moeen rode his luck for 114 (74 balls, 12 fours and five sixes) - pyrotechnics which put Worcestershire in the box seat, though it was Ben Cox's classy 80 (85 balls, nine fours) which brought the best batting of the day.
Warwickshire had found the early going tough against disciplined bowling. Moeen set the tone with two tight overs during which Ed Pollock was caught at deep mid-wicket. Jonathan Trott and Ian Bell fell early but Hain passed 50 for the fifth time in six innings, before reverse-sweeping Ali to short third man. When Dom Sibley was caught behind, Warwickshire were 126 for five.
Ambrose and Rhodes rebuilt, the latter improvising effectively before becoming the first List A victim for Pennington. Ambrose lifted Morris to deep mid-wicket in the penultimate over but 66 runs had arrived from the last five.
Worcestershire's chase suffered early setbacks when Joe Clarke tickled Olly Stone leg-side to the wicketkeeper and Callum Ferguson was bowled by Stone off an inside-edge.
Daryl Mitchell was run out by Jeetan Patel's direct hit and when Brett D'Oliviera fell lbw to Henry Brookes, at 93 for four, the game was in the balance.
Two key partnerships followed as Moeen and Ben Cox added 105 in 13 overs and, after yet another Moeen miscue finally found a fielder, Cox and Ross Whiteley (47, 39 balls, five fours, two sixes) piled on 84 in 13 overs.
When they fell in successive overs, Warwickshire had late hope with 18 needed and three wickets left. After Brookes yorked Joe Leach, Barnard and Pennington took their side within a boundary of victory and, though the latter fell lbw to Barker, Barnard then cover-drove the requisite boundary.