Arul Suppiah's career-best 131 and an exhilarating 54-ball century from Peter Trego led Somerset to an astonishing four-wicket LV County Championship victory over Yorkshire at Taunton.

Set a massive 476 to win in a minimum of 90 overs, the home side reached their target with 4.3 overs to spare. It was the second highest successful run chase in the competition's 145-year history, the fourth highest in first class cricket in England and the eighth highest of all time.

Yorkshire skipper Anthony McGrath had erred on the side of caution by allowing his side to bat on for 20 minutes at the start of the day, adding 34 runs before declaring on 363 for five.

Somerset were up for the challenge from the start as Suppiah and Marcus Trescothick, who fell just four short of a second century in the match, put together an opening stand of 187 in 42 overs. But it was Tregor's amazing onslaught of nine sixes and six fours which finally broke Yorkshire hearts.

Trescothick played superbly for his 96, off 117 balls, with 15 fours and a six, and was unlucky to be out when he played on attempting to leave a ball from Matthew Hoggard.

By then it was a real contest. The score had progressed to 246 when Suppiah, whose only previous Championship century was 123 against Derbyshire at Derby in 2005, had a swing at off-spinner Azeem Rafiq and top edged a catch to McGrath at mid-wicket.

The Malaysian-born opener had faced 175 balls and hit 14 fours and two sixes. Incredibly, his departure saw Somerset turn up the heat by sending in tall pace bowler David Stiff, a former Yorkshire player, as a pinch-hitter.

Stiff responded with four mighty sixes and four fours in scoring 49 off 32 balls. But when he fell to Hoggard with the total on 307 for four and big-hitting Craig Kieswetter could manage only 17 before being bowled stepping back to cut Rafiq, it seemed Somerset would fall short.

Skipper Justin Langer was content to work the ball around while his partners went for the big hits. And it was Trego, coming in at seven, who succeeded in the most spectacular manner.

He scored 42 of his runs in the space of 11 balls as he took 17 off five deliveries from Rafiq and then 24 of an over from Ajmal Shahzad.

Suddenly Somerset needed only five an over from the last nine. But, despite the loss of Langer, Trego went on swinging from the hip to record the fastest first-class century of the season.

Zander de Bruyn hit the winning boundary and within minutes the heavens opened.