Worcestershire skipper Daryl Mitchell and Tom Fell led a strong fightback with the bat on day two of the Specsavers County Championship clash with Northamptonshire at New Road.
The County's second wicket pair put on an unbroken 145 in 36.1 overs to help their side reach 153-1 off 40 overs in reply to Northants 551 all out.
Vice-captain Joe Leach also brought up a half-century – of Championship wickets for the second successive season.
Mitchell achieved his highest Championship score of the campaign and by the close had hit an impressive 86 not out from 126 balls with 14 fours.
Fell continued the promising form he has shown since his return to first team action and his unbeaten 61 off 104 deliveries contained one six and eight fours.
The duo put the Northants attack to the sword on a still flat pitch which the visiting batsmen had also found to their liking.
Northamptonshire tail-ender Chad Barrett completed a maiden century to mark his Championship debut.
Barrett came in at number ten and finished unbeaten on 114.
It was the highest score by a Northants number ten in first class cricket, beating the 106 by Gus Williamson against Cambridge University in 1960.
Barrett became the third century-maker of the innings as he and Steven Crook added 145 in 34 overs – the best Northamptonshire ninth wicket stand in matches against Worcestershire. It surpassed the 137 by John Timms and Reg Partridge at Stourbridge in 1934.
Northamptonshire also registered their highest ever total at New Road, beating the 495 in 1922.
Crook's 145 was his career best score, over-taking his 142 not out versus Australia last summer.
Ed Barnard struck in the first over of the day after Northants resumed on 345-6 when David Murphy (7) was caught at second slip.
Then Rory Kleinveldt (8) became Joe Leach's 50th Championship victim of the campaign when trapped lbw.
The all-rounder has continued to find a way to take wickets despite the flatter nature of the pitches this summer.
Crook and Barrett went on the offensive and the former went to three figures off 142 balls with 15 fours.
Barrett was involved in a bizarre finale in the battle for bonus points when blocking out the final five deliveries of the 110th over from Brett D'Oliveira when Northants required one more run for a fifth batting point.
Crook (145) eventually turned D'Oliveira into the hands of deep square leg. Barrett reached the century milestone soon afterwards with a cover drive for four off George Rhodes and in total he struck one six and 15 fours from his 152 ball innings.
Worcestershire began their reply needing 402 to avoid the follow on and lost D'Oliveira for a duck, caught at second slip off Sanderson.
Mitchell and Fell then batted in untroubled fashion and Mitchell brought up a composed 82 ball half century with seven boundaries.
Fell went to his fifty off 104 balls with a six and eight fours.