Notts Outlaws staged a measured fightback to secure victory at New Road and a home quarter-final at Trent Bridge.
Notts will host either the third or fourth placed team in the South Group on Saturday 6th, Sunday 7th or Monday 8th August as they look to secure one of four finals day spots at Edgbaston.
Worcestershire appeared to be in the driving seat as Moeen Ali's half-century laid solid foundations in reply to the Outlaws' total of 152 all out.
The third umpire gave Ali out after Samit Patel's sharp throw gave Chris Read ample time to complete a run out despite having accidentally flicked off one of the bails before the ball arrived.
Manuel, Kervezee and Shakib scored 20s at virtually a run-a-ball but Notts turned the screw to restrict them to 142-5 with Luke Fletcher's economical return of 1-24 from four overs earning him the champagne.
"It's very pleasing when game plans prove to be effective and thankfully I was able to execute my yorkers at the end," said Fletcher.
"We're unbeaten at Trent Bridge in this competition this year and that underlines the importance of securing a home quarter-final which we've done with games to spare.
"I thought that Worcestershire had out batted us but Samit and Adam bowled very well to slow their rate and we were able to keep them out."
Manuel was stumped by Read having been drawn out of his crease by the guile of Samit Patel (1-21), Kervezee was bowled by Andre Adams and Shakib was caught on the boundary by his compatriot Tamim Iqbal.
Alex Hales (39) and Tamim Iqbal (35) gave Notts a solid start with an opening partnership of 69 but the potential for a score approaching 200 evaporated as Worcestershire chipped away to claim the tenth wicket with the final ball of the innings.