Worcestershire paceman Charlie Morris again destroyed the Somerset top order to put his side on course for victory in the LV = County Championship clash at New Road.
Morris repeated the four wicket burst of his opening spell in the first innings as Somerset were reduced to 36-6 on a blustery third morning.
Joe Leach again provided excellent support with two wickets after the visitors had started their second innings 152 runs in arrears.
James Hildreth and Lewis Gregory provided some resistance in a seventh wicket stand of 38.
But Jack Shantry removed the latter to the last ball before lunch when Somerset were 74-7 still 78 short of avoiding an innings defeat.
Morris bowled 11 overs on the trot and registered figures of 11-3-26-4 while Leach finished his eight over burst with 8-3-22-2.
Morris took the new ball from the Diglis End and struck with his second delivery when Somerset skipper Marcus Trescothick pushed forward and was bowled for a duck.
The Worcestershire paceman then broke through in successive overs to dismiss Johann Myburgh and Tom Cooper. Myburgh (6) jabbed at a Morris delivery and keeper Ben Cox held onto a good low catch away to his right.
Then Cooper was comprehensively bowled for seven to leave Somerset perched on 16-3.
Leach got in on the wicket-taking act by also striking twice in two overs.
Jim Allenby (1) was bowled and then Alex Barrow (0) drove loosely and was caught by Alex Gidman at first slip to leave Somerset on 19-5.
Peter Trego seemed intent on an ultra aggressive approach but after making 14 he lofted Morris to deep mid wicket and Sachithra Senanayake held onto a good catch.
Morris then had figures of 8.3-3-13-4.
Hildreth played some flowing shots and was given some solid support by Gregory
But Shantry ended Gregory's resistance on 14 when he edged through to keeper Cox to leave Hildreth unbeaten on 31.
