Sussex recovered from an onslaught by Justin Langer and Marcus Trescothick to start their FP Trophy defence with an outstanding win.

Richard Montgomerie's chanceless 125 helped the Sharks to 287-5 from their 50 overs but that looked no more than competitive on a typical Taunton featherbed.

And when Somerset's left-handed openers needed just 62 balls to knock off 101 of the target, Sussex must have feared the worst.

Chris Adams had to withdraw his new ball bowlers Rana Naved and James Kirtley after just five overs, by which time Somerset had posted 62, and Mushtaq Ahmed was into the attack as early as the 11th over with fielding restrictions still in place.

It was a gamble but it paid off. Langer played with more fluency, hitting 38 of his 46 in boundaries before he top-edged the leg-spinner's second ball.

The sight of Trescothick cutting loose will have delighted more than just the boisterous Somerset fans knocking back pints of cider in the old pavilion. How new coach Peter Moores would love to have him opening the England batting this summer.

But he fell to a brilliant diving catch on the mid-wicket boundary by Ollie Rayner after hitting six fours and two sixes, one of which bounced into the River Tone off the roof of a stand.

Rana returned to have James Hildreth caught behind but Cameron White and Ian Blackwell seemed to have ensured Somerset did not squander such a good start. They added 82 in 18 overs without too much fuss when Adams pulled another rabbit out of the hat.

He brought back Robin Martin-Jenkins, whose first two overs had conceded 24, and in the space of four balls the all-rounder removed both batsmen when they were well set.

White pulled to deep square-leg and Matt Prior, whose work standing up to the seamers was excellent, held Blackwell off the thinnest of edges.

Suddenly the momentum was all Sussex's. Martin-Jenkins took two more wickets in successive overs and Rana mopped up the tail in spectacular style with two heat-seeking yorkers as Somerset lost their last seven for 38 runs in nine overs. Martin-Jenkins finished with 4-50 and the man-of-the-match award, which is some feat at Taunton.

Adams said: "At 101-0 in the tenth over we were pretty much out of it. I'd tried everything I could but Mushy took two wickets and pulled it out of the bag.

"This team never gives up and that gives me the most satisfaction about our performance. Monty held the innings together and the seamers bowled brilliantly at the end as a unit."

The big positive for Sussex earlier on had been the eighth one-day hundred of Montgomerie's career.

Sussex needed Montgomerie's resilience early on when the new ball nipped around under sultry skies and Somerset took three wickets in 15 overs to justify Langer's decision to bowl first.

They included Rayner, who came in at No.3 on his competition debut but found it difficult to get any momentum.

That was supplied by Murray Goodwin who reached 25 without hitting a boundary before pressing the accelerator.

Langer employed eight bowlers but it had little effect and if Montgomerie and Goodwin had been there at the end Sussex would have posted 300-plus.

But Goodwin, who made his runs off 81 balls with six fours and a six, drove to mid-on in the 47th over and Montgomerie was held on the mid-wicket boundary in the 48th, having hit ten fours in his 161-ball innings.