|LV= County Championship - Division One, Taunton|
|Close, day one: Somerset 409-7 v Durham|
|Somerset 5pts, Durham 2pts|
Marcus Trescothick scored a fifth century in 10 matches as he passed 1,300 runs for the season on day one against Durham.
The former England opener made 163 and shared stands of 98 with Arul Suppiah (52) and 133 with Nick Compton (56).
Murali Kartik (25 not out) and Alfonso Thomas (23 not out) put on an unbeaten partnership of 49 to take Somerset to the close on 409-7.
On a day of toil for Durham's bowlers, Mitch Claydon returned figures of 4-84.
But the day belonged to Trescothick, who confirmed his position as the leading run-maker in county cricket, to take his season's tally in the competition to 1,373 at an average of over 80.
Trescothick's innings lasted 226 balls and contained one six and 23 fours.
The visitors did produce a comeback after the home side had eased to 231-1, with Claydon taking the wickets of Suppiah and Compton, as well as Chris Jones and Peter Trego.
Former England bowler Steve Harmison was far less successful, his 10 overs going for 65, including four wides and three no-balls.
Ian Blackwell (2-53) enjoyed his return to Taunton, claiming the wickets of Trescothick and Craig Kieswetter for 15, while Thomas and Kartik saw Somerset past 400 and to maximum batting bonus points.