Worcestershire spinner Ian Fisher played a key role with three late wickets top help beat his old county Gloucestershire at New Road.
Defending a total of only 145-7, Steve Rhodes' men looked for the taking.
But, although star Australian Ashley Noffke, top scorer with the bat on 34, went for 33 off three overs, the rest of the home attack responded superbly.
Chris Whelan, Gareth Batty and Daryl Mitchell all took two wickets, while Fisher turned the screw with 3-16.
Worcestershire had looked on the back foot after slumping to 46-4, with Vikram Solanki, Steven Davies, Moeen Ali and Ben Smith all back in the hutch.
But the ever reliable Daryl Mitchell played the anchor role, first with Stephen Moore (29), then with Noffke, as his 32 off 36 balls helped the home side post a defendable score.
And once the visitors had slid rapidly from 41-0 to 54-3, losing opening pair William Porterfield (25), Hamish Marshall and skipper Alex Gidman for a fourth ball duck, the Worcester attack did the rest.