COUNTY CHAMPIONSHIP DIVISION ONE, Hove:
16 - 19 June 2009 (Play begins 1100 BST)
CLOSE OF PLAY, DAY ONE: Somerset 314-9 (Somerset 3pts, Sussex 3 pts)
Zander de Bruyn (left) helps Marcus Trescothick acknowledge his century
Marcus Trescothick hit a century for Somerset as Sussex's Piyush Chawla enjoyed another good day with the ball for his new county at Hove.
Indian leg-spinner Chawla, who took eight wickets and hit a maiden first-class ton in Sussex's win at Worcestershire, this time took 5-95.
He bowled 33 overs unchanged from the sea end as Somerset subsided from a promising 138-0 to close on 314-9.
Trescothick hit 17 fours in his 109 off 182 balls before being run out.
Somerset had made serene progress after winning the toss during the morning session, Trescothick and Arul Suppiah taking advantage of superb batting conditions on a slow, dry pitch.
But, in mid-afternoon, Chawla struck with the first and last deliveries of the 47th over to change the complexion of the day. Suppiah (49) was leg before playing back to a googly and James Hildreth defeated by a top-spinner which bowled him between bat and pad.
Trescothick has made a half-century in every Championship game this season but this was only the second time he has converted it to a hundred.
He looked in the mood for a big score when run out, taking on Jason Lewry's arm at mid-on and being comfortably beaten by a direct hit to the non-striker's end.
MARCUS TRESCOTHICK'S TONS
14 in 76 Test matches for England
19 in 150 first-class matches for Somerset
28 one-day centuries (12 for England)
Chawla then struck twice in three overs after tea to put Sussex in control. Skipper Justin Langer was leg before sweeping, although he clearly felt he had hit the ball, and Craig Kieswetter was superbly taken by England wicketkeeper Matt Prior, who had a good day behind the stumps, off a thin outside edge.
After Zander de Bruyn (50) had become Chawla's fifth victim, off-spinner Chris Nash gave excellent support after tea, picking up a deserved wicket when his arm ball knocked back Alfonso Thomas's off stump.
Peter Trego and Championship debutant Max Waller steadied their side with an eighth-wicket stand of 44 but Jason Lewry returned to the attack to bowl Waller in the second over with the second new ball.
David Stiff was then bowled off his pads by left-armer Lewry. And, after being dropped at third slip by Andrew Hodd, last man Charl Willoughby hung around long enough to ensure Somerset a third batting point and Trego (50no) his half-century.