Worcestershire had to be content with one breakthrough with the ball after securing maximum batting points on day three against Gloucestershire at Bristol.
Joe Clarke scored a career best 135 as Worcestershire earned a first innings lead of 31 in reaching 411 all out.
Ben Cox, Matt Henry and Jack Shantry also made useful contributions with the bat during the morning session as the County edged past Gloucestershire's first innings total of 380.
But Gloucestershire made a strong reply in their second innings and reached 129-1 from 33 overs by tea – a lead of 98.
Ed Barnard enjoyed the one success when Cameron Bancroft (29) was caught behind by Cox with 49 on the board.
Chris Dent (45) and Ian Cockbain (48) added an unbroken 80 by the interval.
Worcestershire resumed on 297-5 with Clarke on 103 and Cox 59 and there was a bizarre start to the day.
Kieran Noema-Barnett bowled the first delivery to Cox whose bat broke into two when playing a defensive stroke.
Clarke on 106 was dropped in the covers off Noema-Barnett and the new ball was immediately taken when due with the total 310-5 after 80 overs.
As with the Worcestershire bowlers yesterday morning, the new ball brought a stream of wickets.
Cox, after making a fine 69 from 132 balls with 11 fours, was caught behind off Liam Norwell to end a stand of 155 in 42 overs with Clarke.
In the next over Worcestershire vice-captain Joe Leach shouldered arms to the first ball he received from David Payne and was bowled for nought.
Barnard (9) then edged Norwell to second slip to leave Worcestershire on 331-8.
Clarke decided to go onto the attack and picked up four boundaries in the space of five deliveries from Josh Shaw to take the score past 350.
He was well supported by Henry and the pair added 39 for the ninth wicket before Clarke's fine knock eventually ended.
He was bowled by Norwell after striking 17 fours in his 175 ball knock.
Further resistance came from Henry and number eleven Shantry who added 41 for the tenth wicket to take the County past the 400 mark.
Shantry was eventually caught at mid wicket off Payne for 13 to leave Henry unbeaten on an aggressive 42.