Somerset warmed up for Twenty20 Cup finals day tomorrow in perfect style as Gloucestershire's last hope of a one-day trophy in 2009 was ended by a dreadful capitulation at Bristol.

John Bracewell's side now have only County Championship promotion to aim for after surrendering by eight wickets as the Sabres coasted to their target of 117 with more than 21 overs to spare to move up to second place in Pro40 Division One.

The floodlights brought to the County Ground were turned on at the break but were never needed as the game ended in beautiful sunshine just after 8pm.

Gloucestershire's woe was worsened by the truly bizarre decision to play the theme tune from the American sitcom Happy Days after every dismissal.

Career best one-day hauls from recalled seamers Alfonso Thomas and Mark Turner – 4-18 and 3-27 respectively – put the skids under the Glo'sters.

In reply, Trescothick was initially able to bat relatively circumspectly, although two fours and a monstrous pulled six off James Franklin served notice of his potential.

Craig Kieswetter played on to Jon Lewis for 11 but Ian Saxelby's entry into the attack saw Trescothick run at him and launch him straight for four.

James Hildreth was then reprieved twice, on seven and 11, as Kadeer Ali dropped an absolute sitter before Richard Dawson put down the second chance at slip.

Trescothick's second six – an effortless straight drive off Franklin – brought up his fifty in 44 balls and another huge maximum off Steve Kirby added to the domination.

Hildreth finally fell when he top-edged Franklin to fine-leg for 19 before Trescothick showed the subtle side of his game by twice glancing short balls over the wicketkeeper for four.

The left-hander's fourth six – off Dawson – was the winning hit as he ended on 80 not out.

As far as Gloucestershire were concerned, the rot set in as early as the second ball of the match when Thomas got one to lift to Kadeer, who fended behind to Kieswetter.

Two balls later it was 0-2 as Thomas got one to move away from Alex Gidman, who nicked low to the keeper.

Some sensible consolidation was required, but there was none of that as Franklin tried to slash Phillips through the off-side but only found the hands of Wes Durston at second slip for four.

Will Porterfield(13), Hamish Marshall (23), Chris Taylor (2) and Dawson (0) all went to leave the hosts 51-7, but Lewis and Steve Adshead added 50 in nine overs before Lewis (23) miscued the returning Thomas to hand Trego his third catch.

Turner also returned for a second spell to york Saxelby for six before top-scorer Adshead (34) was the last to hole out as he mis-hit to Phillips at mid-on to give Thomas a fourth scalp.

The overwhelming feeling was one of sympathy for the 3,000 crowd.

The public address announcer had highlighted the chance to sign up for life membership of the club. Exactly how many took up the offer last night is not known.