Worcestershire 178 for 6 (Wells 2-26) beat Lancashire 149 (Salt 44, D'Oliveira 4-20) by 29 runs
Jos Buttler suffered disappointment in his first match since being appointed England's new white-ball captain after an astonishing Lancashire Lightning batting collapse in a 29-run defeat against bottom-placed Worcestershire Rapids at New Road.
Eoin Morgan's replacement was dropped before he had scored but then smashed 42 off 29 balls with three sixes and two fours and he and Phil Salt plundered 85 from 8.2 overs in pursuit of a 179 target.
The Lightning looked well on course to seal the victory that would have booked their place in the quarter-finals.
But then Club Captain Brett D'Oliveira's career-best T20 return of 4-20 was the centre part of a dramatic reversal in fortunes for the Lightning.
Ten wickets went down for 64 runs in 11.1 overs to leave Lancashire's hopes of qualifying for the last eight now hanging in the balance heading into their final game with Birmingham Bears on Sunday.
It was a mixture of poor strokeplay and some inspired bowling as Worcestershire, the 2018 winners, celebrated their second win of the campaign.
The Rapids made two changes with Jake Libby and Dillon Pennington replacing Ed Pollock and Adam Finch.
They were put into bat and Libby and D'Oliveira gave the Rapids a solid start in contrast to their trend this summer of losing too many wickets in the powerplay.
Their opening stand was worth 49 in 5.1 overs before Libby (18) skied Luke Wood to mid-wicket.
D'Oliveira raced onto 33 before he fell to a catch at long on against the bowling of Luke Wells.
Rapids captain Moeen Ali looked in good touch and a six over mid-wicket off Wood sailed out of the ground.
He had made 31 from only 17 deliveries and added 51 in 5.2 overs with Colin Munro before the pair departed in successive overs.
Moeen picked out cover off Wells and then Munro, drilled Matt Parkinson straight to long on.
But then recent signing, Kashif Ali, provided some acceleration with 27 off 15 balls including two sixes before he perished at deep mid wicket off Tom Hartley.
Ed Barnard (11) was caught at mid-off but then Gareth Roderick produced the shot of the innings, a six over fine leg off Gleeson.
When the Lightning batted, Mitchell Stanley bowled a superb first over with plenty of pace.
Buttler was fortunate to survive when he edged the second legitimate bowler from the 21-year-old with Moeen spilling a straightforward chance
He managed only two runs off his first seven balls but then smashed Stanley for six over wide mid on and then a scoop shot against the same bowler brought another maximum.
The powerplay yielded 61 runs and Buttler looked set for a major contribution until he failed to connect properly with a full-toss from D'Oliveira and holed out to backward square leg.
It was the start of a dramatic change-around in fortunes for the Lightning.
Steven Croft was caught behind off Barnard and then D'Oliveira dismissed Salt, 44, and Dane Vila with successive balls before Tim David holed out to long on in his next over.
Moeen came into the attack and removed Danny Lamb and Luke Wells in successive overs before Pat Brown's two wickets helped to polish off the innings.
