Greg Smith's maiden LV= County Championship century for Essex guided the visitors into a strong position on the opening day against Gloucestershire at Bristol.
The 30-year-old South African hit an unbeaten 149 as his side ran up 333-7 after losing the toss. Owais Shah contributed 34 and Ben Foakes 32, while Will Gidman and David Payne claimed two wickets apiece.
Former Derbyshire batsman Smith was dropped on 19 by Michael Klinger at third slip off Payne and went on to face 274 balls, hitting 17 fours and a six.
After opting to field first, Gloucestershire were soon celebrating a prized scalp when India Test player Gautam Gambhir was bowled by Gidman off an inside edge for a duck with the total on nine.
It was 46-2 in the 15th over when Jaik Mickleburgh, on 26, was well caught by wicketkeeper Gareth Roderick, having got an inside edge to a delivery from the recalled Graeme McCarter.
Smith survived his second chance on 41 when Gidman failed to hold a tough one-handed catch at gully off Craig Miles and went on to a half-century off 98 balls, with four fours, having spent 21 deliveries on 48.
Shah looked in confident form as the pair added 80 either side of lunch. But with the score on 126 he played down the wrong line to Miles and was pinned lbw, having hit seven fours in a fluent 72-ball knock.
Ryan ten Doeschate helped Smith add a further 45 in nine overs, contributing 24 to the stand, before edging Benny Howell to Roderick attempting to drive.
Smith moved relentlessly towards his century and reached it with a sweet cover-driven four off McCarter, having faced 207 balls and extended his boundary count to 10 fours and a six.
Gloucestershire took the new ball in the 81st over with Essex 259-4 and Gidman struck with it as Foakes edged to Chris Dent in the slips.
Foakes had ridden his luck at times, facing 84 balls and striking four fours in a stand of 94 with Smith. James Foster looked more assured, but on 26 edged Payne up in the air and Klinger took the catch running back from gully before Graham Napier fell off what turned out to be the final ball of the day.