Sussex tossed away the opportunity to claim a second totesport League win of the season after they failed to defend a formidable 267-9 against Yorkshire at Headingley.

Australian left-hander Phil Jaques, a prolific run-scorer for Northamptonshire last season in his first in England, showed that his powers have not diminished with a switch of counties by making 105 and guiding his side to a five-wicket win with four balls to spare.

Jacques swatted Robin Martin-Jenkins for his third six in the 43rd over to bring up his century off just 82 balls (9x4) and when he fell in the penultimate over the job was done.

It was a day to forget for three of Sussex's most experienced bowlers.

James Kirtley conceded 70 runs on his return to the one-day side while Martin-Jenkins, who took the new ball with Mohammad Akram, was scarcely more effective, conceding 60 runs in his nine overs while Jason Lewry finished with 2-67 from 8.2.

There was no margin for error on a flat pitch although Akram (1-33) and Mushtaq Ahmed (0-37) fared better.

However, Akram dropped England's Anthony McGrath on five and how costly that was. McGrath went on to put on 100 in 15 overs with Jacques to lay the foundations for Yorkshire's third successive win in Division Two.

Sussex's 267-9 was no more than par in ideal batting conditions and they would have scored more had it not been for the sort of collapse which would have embarrassed a school team.

Chris Adams, making his 200th appearance in the competition's various guises, had belted a half-century off just 40 balls and was going well.

But when Martin-Jenkins was fifth out at 233 in the 40th over the wheels fell off.

A few moments later the county were 233-8 having lost four wickets in five balls, including two to needless run outs.

Australian Ian Harvey started the collapse when his stock-in-trade yorker did for Martin-Jenkins and off the next ball Tim Ambrose was beaten by Matthew Wood's throw from deep backward square while scrambling back for a second run that was always a risk.

There was more careless cricket to come. Lewry answered his captain's call for a single to cover far too late and was halfway down the pitch when Harvey broke the stumps to complete one of the more unusual instances of a hat-trick.

Crucially, Adams was leg before to the second ball of the next over from Nick Thornicroft, having made his runs off 48 balls with three fours and two sixes.

Sensible batting at the end from Ahmed, with 19 off 18 balls, made sure there were no further calamities, although Akram was also run out.

Consolation for Sussex had come much earlier in the afternoon with Matt Prior's 72, his second one-day half-century since he returned to the top of the order at the start of the season.

It was hard to believe this was the same batsman who made scores of 0,0,0 and 1 in the same role at the start of last season before the experiment was quietly shelved.

Forty of his runs came in boundaries including two sixes in the first ten overs when the field was in.

Prior and Murray Goodwin put on 106 in 19 overs for the second wicket, but Sussex had to rebuild when Prior top-edged McGrath after making his runs off 75 balls and Goodwin chipped a catch to mid on after making 64 (1x6, 6x4).

Richard Montgomerie came in at No.5 on his return to the one-day ranks and farmed the strike to Adams in a fourth wicket stand of 56 in eight overs. But his return left the side looking unbalanced and when it came to defending their total Adams could have done with the option of a sixth bowler when his seamers were being smashed.

The Sharks seemed to have a measure of control when they took two wickets while the fielding restrictions were in place. Craig White lost his middle stump slogging Akram and when Lewry had Wood caught off an inside edge in the 14th, Yorkshire were 64-2.

But Jaques was soon feasting on anything short or wide and in two partnerships, first with Michael Lumb and then McGrath, he laid the foundations for Yorkshire's victory. The third wicket pair put on 60 in 11 overs when Lumb was run out by Lewry's direct hit running in from fine leg and, as Jaques moved through the gears, he was given excellent support by McGrath (42).

Although Lewry eventually foxed McGrath with a slower ball, Yorkshire's target was down to 50 from six overs and, unlike Sussex, they still had wickets to hand and a batsman in full flow.