DURHAM pulled off their biggest run chase in one-day cricket with the greatest of ease when they continued their defence of the Royal London Cup with a seven-wicket win at Taunton yesterday.

One-day captain Mark Stoneman and Phil Mustard capitalised on a batting paradise in an opening stand of 211 as Durham chased down Somerset's 327 for eight with 21 balls to spare.

Mustard fell for 98 in the 31st over and Stoneman followed for 112 five overs later, bringing in Graham Clark to join Scott Borthwick with 75 needed off 13.5 overs.

The next 16 balls produced only four runs, but there was no need to hurry and Borthwick picked up the pace again in his unbeaten 66 off 47 balls.

Clark failed to take his chance to finish it, hitting a back-foot shot to mid-on to depart for 12, but helping to pick off the remaining runs was a simple task for Paul Collingwood.

Once the openers had 60 on the board after eight overs, 50 of them in boundaries, they were able to cruise towards a target which might have been much higher but for brilliant bowling by John Hastings.

He took five for 41 in his ten overs as the rest struggled to stem Somerset's flow, forcing Stoneman to shuffle his pack like never before.

When Collingwood, apparently unable to bowl ten overs, came on for the 23rd it was the sixth successive over sent down by a different bowler.

Stoneman's tactics worked well until three of the last six overs – those not bowled by Hastings – cost 48 runs.

That resulted largely from Usman Arshad, who took the other three wickets, losing his length after greeting Craig Overton with three excellent yorkers. He couldn't score off those but still thrashed 49 off 25 balls, hitting Arshad for four huge leg-side sixes.

There was also a century by Tom Cooper, the Australian who has played for the Netherlands. He made 104, his first century in what has been a disappointing first season for Somerset.

Arshad conceded 37 in the 45th and 47th overs to finish with 9-0-80-3 before Jamie Harrison was recalled to bowl the 49th and conceded 11.

Harrison had replaced Keaton Jennings as Durham loaded the side with bowlers on what is always a good batting track.

They also don't want to over-bowl Collingwood, who sent down four overs for 16 runs, but it was slightly worrying for Durham that neither spinner could make an impact when Somerset's inexperienced left-armer Jack Leach posed the only problems for Stoneman and Mustard.

It was a surprise when, after conceding only 19 in six overs, Leach was taken off by Jim Allenby, who is captaining Somerset with Marcus Trescothick sitting out this competition.

In his absence, youngsters Tom Abell, from Taunton, and Adam Hose, from the Isle of Wight, opened up after Allenby won the toss and they did well to take the score to 69 in the 13th over before both fell to edged catches.

Peter Trego made a sedate start before taking three fours off a Ryan Pringle over to reach 50 off 52 balls.

But at 158 for two Stoneman wisely recalled Hastings, who persuaded Trego to sky to long leg then had James Hildreth brilliantly caught by Borthwick, diving to his right at slip.

Cooper had hit only two fours when he found the boundary three times in an Arshad over, the last one off the edge to reach 50 off 60 balls, which was a little slow in the context of the game.

Allenby helped to take the score to 236 for four with ten overs left, but the return of Arshad initially brought success.

Allenby tried to give him the charge, changed his mind and steered a catch to Mustard, then Lewis Gregory edged an attempted pull to the wicketkeeper.

Cooper accelerated to his hundred off 95 balls before hooking straight to long leg and Hastings completed his five-wicket haul when he accepted a return catch from Overton with two balls left.

Mustard opened the reply by driving Overton for a straight four, but Stoneman dominated the early scoring, hitting Gregory for three fours in the fourth over while also surviving a big lbw appeal.

In the next over he clattered Overton for four, six, four and he drove a second six off Gregory on his way to 50 off 30 balls.

Mustard was well behind but had re-discovered his best form and nosed ahead by the time he skied a catch.

His 98 came off 91 balls, while Stoneman had faced 108 when he gave Leach a deserved wicket by driving to mid-on.

Somerset weren't helped by Gregory bowling a no-ball to Collingwood, who clobbered the free-hit back over his head for six on his way to an unbeaten 22.