Northants tail-ender Chad Barrett completed a maiden century to mark his Specsavers County Championship debut on a record-breaking day against Worcestershire at New Road.
Barrett came in at number 10 and finished unbeaten on 114 as the newly-crowned NaWest T20 Blast holders switched effectively to red-ball cricket and amassed 551 all out in 144.1 overs.
But Worcestershire launched a strong reply with skipper Daryl Mitchell and Tom Fell scoring half centuries in an unbroken stand of 145 as the home side reached 153 for one by the close.
Barrett’s innings was the highest score by a Northants number 10 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.
Northants 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 for six 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 second time the Worcestershire vice-captain has achieved the milestone.
But Crook and Barrett then flayed the home attack 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.
That was the only blip for the visitors until Crook (145) turned D’Oliveira into the hands of deep square leg.
Last man Ben Sanderson was dropped on nought at first slip off D’Oliveira with Barrett still one short of his century.
But he reached the 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 soon 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. By the close Mitchell had moved onto 86 and Fell 61.