Worcestershire 434-7 lead Derbyshire by 32 runs
Promotion-chasing Worcestershire secured maximum batting points despite a career best performance from Leicestershire spinner Callum Parkinson.
Indian all-rounder Ravichandran Ashwin, wicket-keeper Ben Cox and another all-rounder in Ed Barnard were the main contributors on the third morning as the 400 came up in the 95th over.
But Parkinson kept chipping away with the ball and followed up his three wickets yesterday with another trio of scalps as Worcestershire reached 434-7 off 102 overs by lunch - a lead of 32.
Parkinson then had figures of 37-1-126-6 to surpass his previous best of 4-90 - for Derbyshire against Leicestershire on his first class debut last summer.
Worcestershire resumed on 270-4 and nightwatchman Josh Tongue (10) was neatly stumped by Lewis Hill off Parkinson.
Brett D'Oliveira added 17 to his overnight 121 not out before he was caught and bowled off a leading edge by Parkinson. His 207 ball knock contained one six and 15 fours.
Ashwin and Cox then accelerated Worcestershire towards maximum batting points with a stand of 67 in 10 overs.
But Parkinson returned to the attack after an initial flurry with the seamers via the second new ball and enjoyed a sixth success. Ashwin drove at the 20-year-old and Ned Eckerlsey held onto a fine low chance at cover.
Cox had an escape on nine when Ecklersley spilled the chance at second slip off Dieter Klein but then flourished. New batsman Ed Barnard also survived a stumping opportunity to Hill off Parkinson on 20.
Cox completed his fifty - from 68 balls with five fours and a six - in the final over before lunch with a lofted straight drive for four off Parkinson and also brought up the half century stand with Barnard (26 not out).