Trescothick - key to England's success (Allsport).

By Myles Hodgson, PA Sport Cricket Correspondent

England's hopes of success during the World Cup in South Africa this winter will hinge on the fortunes of their key players. Below we profile the three most important players in England's squad:

MARCUS TRESCOTHICK (Somerset): Arguably the best one-day opener in world cricket, Trescothick has taken to the international stage almost without breaking stride. The transition from making his debut as a replacement for the injured Nasser Hussain in the summer of 2000 to becoming a fully-fledged member of the side has been near seamless.

From the very start of his international career he looked comfortable, scoring 79 on his debut against Zimbabwe at The Oval before hitting an unbeaten 87 in only his fourth match against West Indies at Chester-le-Street and sharing in an unbroken 171-run opening stand with Alec Stewart.

That early success, almost guaranteeing he would not suffer the fate of other young players by losing his place after the first loss of form, enabled him to settle into the demands of international cricket better than any other England player in recent years.

So much so, Trescothick has been established as England's unofficial vice-captain in both formats of the game, leading them for the first time in only his 25th one-day international appearance when captain Nasser Hussain took a break during the mini-tour to Zimbabwe last year.

He also offers an alternative behind the stumps as he proved during last winter's one-day series in India and New Zealand, filling in successfully for James Foster on five occasions after the youngster showed signs of fatigue.

But it is in his aggressive strokeplay where Trescothick truly excels. Demonstrating positive intent from the first ball of his innings, he is particularly strong pulling and driving and has formed an effective opening partnership with fellow left-hander Nick Knight which can be compared favourably with any other in world cricket.

ANDREW FLINTOFF (Lancashire): One of the most explosive batsmen in world cricket when on song, Flintoff has developed from a young player with vast potential at the last World Cup into one of England's key men this time around.

Particularly powerful off his legs and one of the best straight-hitters in the game, such is Flintoff's effectiveness that he was moved up and down the batting order initially as England attempted to discover his best position.

His style seemed ideal for the number three spot when the batsman is often required to take advantage of the first 15 overs of fielding restrictions following an early wicket.

But it was from down the order that he scored a half-century on his debut against Pakistan in Sharjah and also where he hit a match-winning 84 to beat the same opponents in Karachi in 2000.

England have at least demonstrated some flexibility in recent times, moving Flintoff up to number three only last summer and allowing him to come in lower down when he hit 50 off 28 balls against Sri Lanka at Trent Bridge when circumstances dictated.

He is, though, much more than just a hard-hitting batsman and - depending on his rehabilitation following his recurrent groin trouble - has now developed into an effective alternative with the ball, providing economical spells during the middle of the innings. He is also a superb fielder either close in or in the deep.

MICHAEL VAUGHAN (Yorkshire)

Vaughan has been England's 2002 lynchpin in Test cricket - belying his perceived status as an honest, technically sound grafter with an array of shots which have put India, Sri Lanka and finally Australia to the sword.

More than that his increasing fluency at the top of the order has cemented the impression he could be a valuable commodity in the one-day game too, wherever he is used in the top five.

Scoring 900 runs at 90 in 12 innings against Sri Lanka and India in English conditions last summer was merely a warm-up for the ultimate test down under in the first half of England's exacting winter.

His free-scoring 177 at Adelaide was the highlight of England's Ashes campaign.

Seemingly able to dispatch the ball wherever he liked, that opening day of the second Test was as good as it got for Nasser Hussain's team.

That freedom of stroke should ensure that Vaughan has a significant part to play in the forthcoming World Cup.

A total of 56 runs in the first seven innings of a stop-start one-day international career, which is still only 17 matches old, was disappointing.

But he relishes challenges and took it upon himself to gain a place in England's plans for South Africa, adapting to the one-day game to complement his Test match standing.

Scores of 63 and 43 in India 12 months ago and 59 in New Zealand on the tour that followed emphasised that Vaughan can flourish in limited-overs internationals.

All the talk is of who will be employed as a pinch-hitter at first-wicket down should the run-rate be lagging.

Yet if Vaughan was allowed extra time at the crease, England might not need a specialist 15-over bully.

In all too many of his ODI appearances, he has walked into bat in the middle order towards the death of the innings and has never been sent in higher than number four. But should the Trescothick-Knight opening axis falter or the number three spot come up for grabs again Vaughan will be the obvious answer.