England's recent about-turn in one-day form has shown captain Michael Vaughan their World Cup potential.
Vaughan has been told to rest his hamstring for a further week
Vaughan, 32, left the tour of Australia on Saturday to rest his troublesome hamstring before the Caribbean trip.
"Perhaps we were not as far away as people thought. If you get a couple of wins you can build a bit of momentum and go on from there," said Vaughan.
"There has not been a lot of optimism surrounding our chances but it is amazing what a couple of wins can do."
Up until last week, England had lost 24 of their previous 31 completed matches against Test-playing nations.
I really believe we have got a good side to do well in the World Cup
But they beat New Zealand and Australia to force a place in the one-day series finals then upset the hosts again in Melbourne on Friday.
They will take on New Zealand again in St Lucia on 16 March, in their opening game in Group C of the World Cup.
Ashes England and Australia rivals look likely to meet in the Super Eight stage on 8 April in Antigua, but Vaughan has one eye on the final, in Barbados three weeks later.
"We have tested ourselves against the best in Australia and got that experience and who knows, we could be playing them again at the end of April," he said.
"There are a lot of tough teams but we feel that on our day we can beat anyone.
"It is the sort of competition where if you go in with a bit of form and carry it on it can take you a long way."
England name their 15-man World Cup squad on Wednesday, with Vaughan expected to be included as he only needs to rest his injury for a further week.
Wicket-keeper Paul Nixon is another player likely to secure a spot, highlighting his batting ability with a cameo 11
"I really enjoy the focus, the buzz and intensity of the one-day game," said Nixon. "I am just loving it, I am living the dream.
"I care and I want to be there, it would be an amazing achievement and I really believe we have got a good side to do well in the World Cup."