Sussex frittered away the chance to make a winning start to their Benson and Hedges Cup campaign at Chelmsford.

It was the sort of collapse skipper Chris Adams must have hoped had been consigned to the dim and distant past.

After James Kirtley had taken career-best figures of 5-33, Sussex were cruising towards their target of 207 when Adams' opposite number Ronnie Irani returned to the attack and blew away their middle order with a sensational spell of 4-12 in 15 balls.

Adams was first to go for 54 and Murray Goodwin, Tony Cottey and Will House quickly followed as Irani pitched the ball up and waited for compliant batsmen to make mistakes.

John Stephenson, back in Essex after five years with Hampshire, chipped in with the wicket of Robin Martin-Jenkins as Sussex collapsed from 103-1 to 114-6 in five overs.

When the rain, which had been threatening for some time, finally swept over the ground, they were 25 runs behind on Duckworth-Lewis calculations.

An hour later the scorers had worked out that Sussex would need to score another 66 off 7.4 overs. But there was just time for Jon Dakin to finish an uncompleted over when the heavens opened again.

When the match was abandoned half-an-hour later Essex had won by 20 runs and maintained a stranglehold on Sussex in the competition which has seen them win 12 of their 16 meetings.

Coach Peter Moores will have kept the inquests short and sweet. He prefers to look forward rather than back but even he must have found it hard to fathom how Sussex, who had dominated most of the contest, had ended up losing.

On paper their new-look one-day side has a nice balance to it with three all-rounders and much more batting depth. Consolation for Sussex came in the performances of Kirtley and Michael Yardy whose bowling has improved considerably thanks to the work he did in South Africa during the winter.

But it does not matter if you play one batsman or eight if your shot selection is poor and too many Sussex players were guilty of that yesterday.

Yet it all started so well. Although Tim Ambrose was bowled through the gate by Irani in the third over, their grip on the match was comfortably maintained by Adams and Richard Montgomerie who never looked troubled by Essex's assortment of seamers while they were adding 88 in 21 overs for the second wicket.

It all started to go wrong in the 24th over when Adams, who had just reached his tenth Benson and Hedges 50 off 73 balls with six fours, drove well outside off stump and was caught at point.

Irani did just enough to find Goodwin's edge with his next delivery and all of a sudden Essex's self-belief returned.

In Irani's next over Cottey followed an outswinger and edged it to second slip and Sussex lost their fourth wicket in 22 balls when Stephenson deceived Martin-Jenkins with extra bounce to have him caught behind.

Will House loosened the shackles by driving Irani through the covers for four but he perished to the next ball, slashing off the back foot straight to point.

Irani was duly named man-of-the- match which was a desperate shame for Kirtley who had earlier produced two superb spells to offer further evidence that, complete with re-modelled action, he is an even better bowler this season.

There was some moisture in the surface early on and Kirtley and new-ball partner Martin-Jenkins exploited it to the full to reduce Essex to 18-4 in nine overs after Adams had won the toss.

A peach of an inswinger with his fourth ball knocked back Stephenson's off stump and when Martin-Jenkins trapped Graham Napier leg before half-forward with his first delivery the hosts were 1-2.

Kirtley took the key wicket of Andy Flower in his second over when the Zimbabwean fell lbw trying to work the ball down to third man while Dakin was caught behind after being drawn forward by one which held it's line.

There was not much wrong with Sussex's support bowling either although once the new ball had lost it's hardness scoring became easier on what was essentially a good pitch.

Irani and Essex's new recruit Aftab Habib put on 77 in 21 overs to rebuild the innings when Yardy had Irani caught behind off a thin edge after making 47 and the left-armer claimed his second wicket when Darren Robinson drove him hard to mid on where Kirtley took a good catch tumbling to his left.

Yardy finished with 2-44 and also had Irani dropped by Mark Davis at deep mid-wicket on 38. It was not Davis's day as he also dropped Paul Grayson off his own bowling.

Habib was taken at short mid-wicket for 46 to give Billy Taylor belated reward and it was left to Grayson, who nudged his way to an unbeaten 49 off 55 balls, to organise the tail and lead his side to respectability.

Kirtley yorked Ashley Cowan with the second ball of his new spell before he had James Middlebrook caught at long on in his final over and claim a five-wicket haul in one-day cricket for only the second time.

Surrey's defeat at Lord's has thrown the south qualifying group wide open.

Sussex head to Canterbury on Wednesday and although they are unlikely to make many changes defeat against Kent will leave them struggling to qualify for the quarter-finals for the third successive season.