Somerset were left to rue a potentially expensive miss as they try to shore up second place in the County Championship Division One table.

On day one of their final first-class game of the season they dropped Worcestershire opener Daryl Mitchell on 28 and saw him go on to smash 232 not out.

The already relegated visitors, who won the toss, closed on 408-4 to make light of a green pitch at Taunton.

Somerset went into the game with the second-place prize money of £225,000 as their target. Third will get £115,000 and fourth will be awarded just £35,000.

But the best and worst of wicketkeeper Craig Kieswetter was on show as he dropped Mitchell and then pulled off a stunning, diving effort to get rid of Moeen Ali.

The future England prospect's batting cannot be faulted and Somerset recognised his talent by awarding him his county cap - along with Arul Suppiah - during the lunch break.

But he still has work to do on his keeping during one-to-one training sessions with former England captain Alec Stewart.

Mitchell edged Ben Phillips to Kieswetter who fumbled the chance and departing skipper Justin Langer at first slip was unable to hold the rebound. At the close, 204 runs later, Mitchell was still going strong.

The final day of Somerset's previous match at Taunton - against Lancashire - had been wicketless and they made their first breakthrough of yesterday at 12.05pm - exactly seven and a half hours of playing time since their last wicket.

Stephen Moore tried to pull David Stiff and edged behind to Kieswetter for 32 and on the stroke of lunch the dangerous Vikram Solanki's ambitious drive at Charl Willoughby ended in the hands of Marcus Trescothick at first slip for 15.

After lunch, Kieswetter dived full length to his left to grab a nick from Moeen (one) in front of second slip.

Stiff claimed his second wicket when he got Alex Kervezee to sky to Suppiah at point for 19 but Mitchell continued to plough on.

Despite making just four previous Championship fifties in 14 games this season, Mitchell passed his previous career best and never looked in any trouble.

He shared an unbroken stand of 217 with David Wheeldon, who was making his fourth career appearance having scored just 29 previous runs.

But the 20-year-old reached his maiden fifty with eleven fours en route to 87 not out after Mitchell's 38th four took him to his double century from his 262nd ball.

Yes, Taunton is consistently the flattest pitch in the country but the manner in which two unheralded players creamed the pick of the Somerset bowling underlined that it had also been a flat performance with the ball. Only Phillips (20-0-48-0) and Suppiah conceded fewer than four runs per over.

Taunton has seen two triple centuries this year - from James Hildreth and Murray Goodwin - and few would bet against a rare hat-trick of 300s being achieved.

Against the rock bottom side in Division One, Somerset's victory chances have almost gone after Worcester hit 35 fours in the final session.

They will need to remove the visitors' tail quickly and rack up a massive score of their own.

Trescothick requires 255 runs from his final match to reach 2,000 for the season and a knock like that will be needed to give Langer's men any hope at all.