Warwickshire 355 for 9 dec and 68 for 0 lead Worcestershire 410 for 7 (Mitchell 110, Libby 84, Fell 55, Haynes 51) by 13 runs
Daryl Mitchell completed his first century against Warwickshire in first-class cricket as Worcestershire secured four batting points to boost their hopes of qualifying from the Bob Willis Trophy Central Group.
The veteran opener has now scored first-class hundreds for Worcestershire against all other counties except Surrey as his side eked out a first-innings lead of 55 with their third 400 plus score in four matches in the competition.
Their solid performances with the bat have been in stark contrast to their failings with the bat in the County Championship last season. Only once did they top 400 - in the opening game against Leicestershire at the Fischer County Ground - and this was another indication that the extra work put in during the winter to improve at red-ball cricket is paying dividends.
Half-centuries from Jack Haynes and Tom Fell plus late momentum provided by Ben Cox and Ed Barnard built on the efforts of Mitchell and fellow opener Jake Libby and enabled Worcestershire, who are vying with Somerset for top spot, to total 410 for 7 in their 120 overs.
Warwickshire paceman Oliver Hannon-Dalby was rewarded for his persistence on a slow pitch still offering little encouragement for the bowlers with three wickets.
The visitors made a solid start to their reply with openers Will Rhodes - a double century-maker in the first innings - and Rob Yates putting on an unbroken 68 either side of a short break for bad light.
With heavy rain forecast for day four, the likeliest outcome would appear to be a draw but the 13 points Worcestershire would accrue should that be the case would keep them well in contention - with Somerset due to visit Blackfinch New Road for the final group game on September 6.
Worcestershire resumed on 170 and only seven runs had been added in six overs when Hannon-Dalby made a breakthrough courtesy of a superb catch by Tim Bresnan. Libby, on 84, got a thick edge and Bresnan at slip held onto the chance at full stretch one-handed away to his right.
The former Nottinghamshire player had batted for nearly four hours and struck seven fours in his 189 ball knock. His tally of 417 runs in the competition has only been surpassed by Ben Slater for Leicestershire and Nottinghamshire.
A single to third man off Craig Miles took Mitchell to three figures from 223 deliveries with 12 boundaries. It was his 37th first class hundred for the County since making his debut 15 years ago. The 35-year-old advanced to 110 before he drove Miles to cover point where Rob Yates held another sharp catch with the total 214 for 2.
Fell, fresh from his first hundred in five years at Northampton last week, and Haynes upped the tempo during a stand of 89 in only 23 overs. Haynes gave another demonstration of his potential with some powerful strokes and Fell went down the wicket to Alex Thomson to bring up the 250 and a second batting point with a lofted straight drive.
A single off Thomson took Haynes to his half century from 77 balls - a rapid effort in the context of the game - with seven fours before on 51 he was caught at deep mid-off from the bowling of Ryan Sidebottom.
Fell completed a 96 ball half-century with seven fours before he was yorked by Hannon-Dalby who in the same over bowled Riki Wessels via an inside edge.
Brett D'Oliveira was lbw to Bresnan for 15 at 325 for 6 but Cox and Barnard ensured a fourth batting point was secured in a stand of 82 in 14 overs. Cox continued the run of important late order contributions he has made this summer in racing to 43 off 51 balls before he was lbw to Will Rhodes in the final over of the innings to leave Barnard unbeaten on 29.
Hannon-Dalby's final figures of 26-9-70-3 were well deserved for his perseverance which mirrored that of Charlie Morris for Worcestershire.
Rhodes and Yates experienced few problems in the 23 overs possible in Warwickshire's second innings as they wiped out their side's first innings deficit and earned a lead of 13.