Worcestershire 133 for 2 (D'Oliveira 61*) beat Lancashire 132 for 4 (Buttler 55) by eight wickets with 16 balls to spare
Jos Buttler hit a half-century but was unable to stop Worcestershire Rapids moving to the top of the North Group in the Vitality Blast with an eight-wicket success over previous leaders Lancashire Lightning at New Road.
England wicket-keeper batsman Buttler top-scored with 55 off 46 balls in what was his first Blast fifty of the summer. But Lancashire were kept in check on a slow pitch by an excellent performance from the Rapids attack and restricted to 132 for 4 after opting to bat.
Then an opening stand of 79 in nine overs by Riki Wessels and Brett D'Oliveira ensured the Rapids reached their target with 16 balls to spare. D'Oliveira completed a 36-ball half century and ended unbeaten on 61 from 45 balls with one six and seven fours.
The Rapids made one change from the side which triumphed away to Northamptonshire Steelbacks with Dillon Pennington replacing fellow paceman Josh Tongue while Lightning were unchanged.
Lightning opted to bat after winning the toss on the same pitch used for last Wednesday's tied game with Notts Outlaws. Ben Dwarshuis made the first breakthrough when New Zealander Finn Allen, after making 10, top edged a catch to Charlie Morris at third man.
Liam Livingstone showed his power in smashing Pennington over long off for six but batting was not straightforward on a slow surface. There was a second scalp for the Rapids when Alex Davies on 7 drove Morris to cover.
Lightning scored 39 for 2 in the powerplay, and Buttler was soon into his stride with a reverse sweep for four off Moeen Ali which brought up the 50 in the eighth over. He then lofted his England colleague over the mid-wicket boundary.
Livingstone made 25 off 26 balls and, when he tried to accelerate, he picked out Wessels at long on in D'Oliveira's first over.
Buttler brought up his 43-ball half century in the grand manner when he smashed Sodhi for a huge six over long off. He survived one dropped chance at long off against Morris but was dismissed from the next delivery on 55 with Wessels holding on at long on.
Rapids openers D'Oliveira and Wessels both got off the mark with boundaries in the third man region and the former then flicked Danny Lamb backward of square for successive fours.
The initial powerplay produced 48 runs and no breakthroughs for the visitors. Wessels had a let-off on 20 when he dropped at long on in Matt Parkinson's first over but otherwise runs flowed freely and he pulled the same bowler backward of square for six in his next over.
The opening stand was worth 79 in just 8.5 overs when Wessels, having made 40 off 27 balls, was bowled by Parkinson who then had Moeen on 9 caught at midwicket.
But D'Oliveira continued to impress and lofted Livingstone over mid wicket for six as the 100 came up in the 12th over.