Worcestershire's bowlers toiled away for little reward on the opening day of the Second Eleven Championship match with Derbyshire at Derby.
The home side decided to bat after winning the toss and reached 422-2 off 93 overs before bad light ended play.
Worcestershire skipper Joe Leach struck an early blow as Ben Slater (16) was trapped lbw with 42 on the board.
But then the day was dominated by a partnership of 282 in 63 overs between Paul Borrington and captain Scott Elstone.
Borrington followed up his ton in the Second Eleven Trophy match the previous day by making 121 off 243 balls with 15 fours.
He eventually fell after tea to a good catch at mid wicket by Richard Oliver off Graeme Whiles.
But Elstone went onto finish unbeaten on 212 from 218 balls with three sixes and 29 balls with Adam Hughes 46 not out from 54 balls.
There was a break from rain during the final session but play was able to resume at 6.50pm for 10 overs before bad light intervened.
Chris Russell conceded only 41 runs in his first 17 overs spanning three spells before conceding 18 in his final over of the day.
Derbyshire first innings 422-2 (93 overs): Slater lbw Leach 16, Borrington c Oliver b Whiles 121, Elstone not out 212, Hughes not out 46, Extras 27.
Bowling: Russell 18-3-59-0, Cessford 15-3-56-0, Whiles 17-0-89-1, Leach 18-2-76-1, Harrison 9-0-37-0, D'Oliveira 7-0-45-0, Rhodes 8-0-44-0, Hepburn 1-0-4-0.