Worcestershire were made to work hard for wickets as an unbeaten century from James Hildreth helped Somerset to close on 349-5 on day one of the LV = County Championship clash at Taunton.
Jack Shantry and Joe Leach both picked up two wickets after the home side had been put into bat in overcast conditions.
But Somerset batted consistently all down the order after the early loss of Johann Myburgh for a duck.
Skipper Marcus Trescothick, Tom Cooper and Jim Allenby all scored half century to supplement the efforts of Hildreth who registered his fourth first class ton of the campaign.
He finished unbeaten on 133 from 182 balls with 21 fours.
It was Shantry who broke through in the fourth over by trapping Myburgh lbw with just eight runs on the board.
Trescothick and Tom Cooper added 108 for the second wicket before the latter on 57 edged the third ball after lunch from Joe Leach to Alex Gidman who clung onto a good catch at first slip.
Trescothick, who was dropped off the final delivery before lunch from Ross Whiteley, passed 23,000 first class runs and advanced to 85 from 175 balls with 17 fours before he swept at Brett D'Oliveira and was bowled.
His stand with Hildreth was worth 93 in 24 overs.
Hildreth, who himself passed the 13,000 first class runs milestone during the day, found another willing ally in Jim Allenby.
The 30-year-old Hildreth completed his 100 out of 289-3 in the 80th over before the second new ball was immediately taken.
It was Shantry who returned to break a partnership of 122 in 34 overs when Allenby (50) was caught behind by keeper Ben Cox.
Nightwatchman Jack Leach was bowled by his namesake Joe for five but Hildreth was still there at the close.