James Foster gave a timely reminder to the England selectors of his qualities as a batsman with his first hundred of the season, having already made a fifty in the first innings.

The Essex wicketkeeper, who reached his landmark off 183 balls with a straight six off Gareth Andrew, held the batting together as his side extended their lead to a potentially match-winning one.

Foster, entrusted with the responsibility at batting at No5, needed to play an innings of substance when Essex lost their fourth wicket soon after lunch at 127. Had Worcestershire broken his fifth-wicket alliance with Ryan ten Doeschate quickly, Essex would have been under real pressure, but the pair put together a crucial stand of 96 in 31 overs to regain the initiative.

Worcestershire's attack was not always patient enough on a slow club pitch that required their seam bowlers to nag away on a consistent line and length. A sore back for Kabir Ali did not help their cause, preventing the country's leading wicket-taker from bowling more than 14 overs.

Ealier, resuming at 10 without loss, Essex lost two quick wickets. Jason Gallian was removed on the second over of the day thanks to a smart leg-side catch by Steven Davies, and Grant Flower was held at first slip. Mark Pettini and Varun Chopra added exactly 50 in 17 overs before the latter was caught at slip to give Kabir his 58th victim of the campaign. Soon after Pettini, who passed 300 first class runs during his attractive 46, came down the pitch to Gareth Batty but skied to point.

Playing meticulously straight and skewing all risk, Foster reached his 50 from 86 balls with six fours, he hit only one more four in his second 50. Ten Doeschate played the part of aggressor until the persistent Imran Arif had both the Dutchman and James Middlebrook caught behind in rapid succession. Graham Napier, cutting straight to backward point, became a second victim for Gareth Andrew, who later had Chris Wright taken at mid-on.

Essex confirmed that Danish Kaneria will require an operation on his spinning finger, thereby ruling him out of the rest of the season. Morris Chambers, the fast bowler, has been scheduled for surgery on his left ankle on September 1 when a bony fragment from the back of the joint will be removed. The injury has been affecting his ability to bowl but he is still able to play until surgery, and his availability will be decided on a game-by-game basis.

Scorecard

Essex: First Innings 282 (R N ten Doeschate 94 not out, M L Pettini 59, J S Foster 55; K Ali 6 for 83, Imran Arif 4 for 84)

Second Innings (overnight 10-0)
J E R Gallian c Davies b Arif 9
V Chopra c Smith b Kabir Ali 38
G W Flower c Smith b Andrew 9
*M L Pettini c sub b Batty 46
J S Foster not out 111
R N ten Doeschate c Davies b Arif 46
J D Middlebrook c Davies b Arif 10
G R Napier c Moore b Andrew 8
C J C Wright c sub b Andrew 10
D D Masters not out 19
Extras (lb 8, w 2, nb 6) 16

Total (8 wkts, 100 overs) 322

Fall of wickets: 1-14, 2-46, 3-96, 4-127, 5-223, 6-237, 7-250, 8-281.

Bowling: Ali 14-3-40-1; Arif 25-2-90-3; Andrew 20-3-59-3; Batty 31-7-98-1; Mitchell 10-0-27-0.

Worcestershire: First Innings 258 (B F Smith 74, G J Batty 60)

Umpires: N L Bainton and M A Gough.